Skype

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Skype
Skype logo.svg
Skype.png
Screenshot of Skype 6.2 on Windows 7
Original author(s) Janus Friis, Niklas Zennström
Developer(s) Skype Technologies S.A.
(Microsoft Corporation)
Initial release August 2003; 10 years ago (2003-08)
Stable release
Written in Delphi, Objective-C, C++ with Qt[14]
Operating system Windows, Windows Phone, OS X, iOS, Linux, Android, BlackBerry OS, Symbian, PSP, PSVita, Xbox One
Available in 38 languages
Type VoIP, Instant messaging, Videoconferencing
License Freemium
Website www.skype.com

Skype /ˈskp/ is a freemium voice-over-IP service and instant messaging client, currently developed by the Microsoft Skype Division. The name was derived from "sky" and "peer".[15]

Skype was first released in August 2003. It was created by Janus Friis (Denmark) and Niklas Zennström (Sweden) in cooperation with Ahti Heinla, Priit Kasesalu, and Jaan Tallinn (Estonia), who supplied the backend which was also used in Kazaa.[16] Skype had 663 million registered users as of the end of 2010.[17] It was bought by Microsoft in 2011 for $8.5 billion. Microsoft's Skype division headquarters is in Luxembourg, but most of the development team and 44% of the overall employees of the division are still situated in Tallinn and Tartu, Estonia.[18][19][20]

The service allows users to communicate with peers by voice using a microphone, video by using a webcam, and instant messaging over the Internet. Phone calls may be placed to recipients on the traditional telephone networks. Calls to other users within the Skype service are free of charge, while calls to landline telephones and mobile phones are charged via a debit-based user account system. Skype has also become popular for its additional features, including file transfer, and videoconferencing. Competitors include SIP and H.323-based services, such as Linphone[21] and Google Hangouts.

Unlike most other VoIP services, Skype is a hybrid peer-to-peer and client–server system. It makes use of background processing on computers running Skype software, and this is reflected in Skype's original proposed name of Sky Peer-to-Peer.

Some network administrators have banned Skype on corporate, government, home and education networks,[22] citing reasons such as inappropriate usage of resources, excessive bandwidth usage, and security concerns.[23]

History[edit]

Skype was founded in 2003 by Janus Friis from Denmark and Niklas Zennström from Sweden.[24] The Skype software was created by the Estonians Ahti Heinla, Priit Kasesalu, and Jaan Tallinn[25] The first public beta version was released on 29 August 2003.[26]

In June 2005, Skype entered into an agreement with the Polish web portal Onet.pl.[citation needed] On 12 September 2007, eBay Inc. agreed to acquire Luxembourg-based Skype Technologies SA for approximately US$2.5 billion in up-front cash and eBay stock, plus potential performance-based consideration.[27]

On 1 September 2009, it was announced that eBay was selling 65% of Skype to Silver Lake, Andreessen Horowitz and the Canada Pension Plan Investment Board for US$1.9 billion, valuing Skype at US$2.75 billion.

Microsoft acquisition[edit]

On 10 May 2011, Microsoft Corporation acquired Skype Communications, S.à r.l for US$8.5 billion.[28] The company was incorporated as a division of Microsoft, and Microsoft acquired all of the company's technologies with the purchase. This was completed on 13 October 2011.[28][29]

Microsoft phased out its long-standing Windows Live Messenger instant messaging service in favor of Skype, although Messenger continues in mainland China.[30] Microsoft began this transition on 8 April 2013, and completed the move by 30 April.[31]

Features[edit]

Registered users of Skype are identified by a unique Skype Name, and may be listed in the Skype directory.[32] Skype allows these registered users to communicate through both instant messaging and voice chat. Voice chat allows telephone calls between pairs of users and conference calling, and uses a proprietary audio codec. Skype's text chat client allows group chats, emoticons, storing chat history and editing of previous messages. Offline messages were implemented in a beta of version 5, but removed after a few weeks without notification. The usual features familiar to instant messaging users — user profiles, online status indicators, and so on — are also included.

The Online Number, a.k.a. SkypeIn, service allows Skype users to receive calls on their computers dialed by conventional phone subscribers to a local Skype phone number; local numbers are available for Australia, Belgium, Brazil, Chile, Colombia, Denmark, the Dominican Republic, Estonia, Finland, France, Germany, Hong Kong, Hungary, Ireland, Japan, Mexico, Nepal, New Zealand, Poland, Romania, South Africa, South Korea, Sweden, Switzerland, Turkey, the Netherlands, the United Kingdom, and the United States.[33][34] A Skype user can have local numbers in any of these countries, with calls to the number charged at the same rate as calls to fixed lines in the country. The countries on this growing list are referred to collectively as the SkypeIn Countries.

Skype supports conference calls up to 25 people at a time. Skype also supports video chat between two people for free. Screen sharing and group video calling is available for Premium subscribers between a maximum of 10 people.[35]

Skype does not provide the ability to call emergency numbers such as 112 in Europe, 911 in North America, 000 in Australia, 100 Call Police in India and Nepal.[36] The U.S. Federal Communications Commission (FCC) has ruled that, for the purposes of section 255 of the Telecommunications Act, Skype is not an "interconnected VoIP provider".[37] As a result, the U.S. National Emergency Number Association recommends that all VoIP users have an analog line available as a backup.[38]

On 14 July 2011, Skype partnered with Comcast to bring its video chat service to Comcast subscribers via their HDTV sets.[39]

On 17 June 2013, Skype released a free video messaging service which can be operated on Windows and Mac OS, iOS, Android and BlackBerry.[40]

On 12 August 2013, Skype released the 4.10 update to the app for Apple iPhone and iPad that allows HD quality video for iPhone 5 and fourth generation iPads.[41]

Usage and traffic[edit]

Year International call market share
2005 2.9 %[54]
2006 4.4 %[54]
2008 8 %[53]
2009 12 %[52]
2010 13 %[55]
2012 34 %[56]

In January 2011, after the release of video calling on the Skype client for iPhone, Skype reached a record 27 million simultaneous online users.[57] This record was broken with 29 million simultaneous online users on 21 February 2011,[58] and again on 28 March 2011 with 30 million online users.[59] On 25 February 2012, Skype announced that it has over 32 million users for the first time ever.[60] As of 5 March 2012, it has broken to 36 million simultaneous online users [61] and less than a year later, on 21 January 2013, Skype had more than 50 million concurrent users online.[62] In June 2012, Skype had surpassed 70 million downloads on an Android Device.[63]

On 19 July 2012, Microsoft announced that Skype users had logged 115 billion minutes of calls over the quarter, up 50% since the last quarter.[64]

System and software[edit]

Client applications and devices[edit]

Skype runs on a number of platforms including Microsoft Windows (XP, Vista, 7, 8), OS X (10.6 or newer), Linux (Ubuntu and others), Android, BlackBerry 10, iOS, Symbian and Windows Phone.

On 29 October 2007, Skype launched its own mobile phone under the brand name 3 Skypephone, which runs a BREW OS.[65]

Skype also offers a Skype Wi-Fi Phone, which is a wireless mobile phone that allows users to make Skype calls, using a wireless Internet connection. The Skype Wi-Fi Phone has an on-screen menu that lets Skype users see who is online and available to talk, similar to what is seen on a PC. It can also be used to talk with non-Skype users. SkypeOut minutes can be used to call any phone for a low price and no monthly fee. The Skype Wi-Fi phone does not contain a web browser and so can not access hotspots that require web-based login or authentication.[66]

Other platforms officially supported include:

  • The Nokia N800, N810 and N900 Internet Tablets, which run Maemo
  • The Nokia N9, which runs MeeGo, comes with Skype voice calling and text messaging integrated however lacks video-calling.
  • Both the Sony mylo COM-1 and COM-2 models
  • The PlayStation Portable Slim and Lite series, though the user needs to purchase a specially designed microphone peripheral. The PSP-3000 has a built in microphone, which allows communication without the Skype peripheral.[67] The PSP Go has the ability to use Bluetooth connections with the Skype application, in addition to its built-in microphone.[68] Skype for PlayStation Vita may be downloaded via the PlayStation Network in the U.S. It includes the capability to receive incoming calls with the application running in the background.
  • Samsung Smart TV has a Skype app which can be downloaded for free.[69] It uses the built in camera and microphone for the newer models. Alternatively a separate mountable Skype camera with built in speakers and microphones is available to purchase for older models.[70]
  • Some devices are made to work with Skype by talking to a desktop Skype client or by embedding Skype software into the device. These are usually either tethered to a PC, or have a built-in Wi-Fi client to allow calling from Wi-Fi hotspots like the Netgear SPH101 Skype Wi-Fi Phone, the SMC WSKP100 Skype Wi-Fi Phone, the Belkin F1PP000GN-SK Wi-Fi Skype Phone, the Panasonic KX-WP1050 Wi-Fi Phone for Skype Executive Travel Set, the IPEVO So-20 Wi-Fi Phone for Skype and the Linksys CIT200 Wi-Fi Phone.

Third-party developers, such as Truphone, Nimbuzz and Fring, previously allowed Skype to run in parallel with several other competing VoIP/IM networks (Truphone and Nimbuzz provide TruphoneOut and NimbuzzOut as a competing paid service) in any Symbian or Java environment. Nimbuzz made Skype available to BlackBerry users and Fring provided mobile video calling over Skype as well as support for the Android platform. Skype disabled Fring users from accessing Skype in July 2010.[71] Nimbuzz discontinued support on request of Skype in October 2010.[72]

Before and during the Microsoft acquisition, Skype withdrew licensing from several third parties producing software and hardware compatible with Skype. The Skype for Asterisk product from Digium was withdrawn as "no longer available for sale".[73] The Senao SN358+ long-range (10–15 km) cordless phone were discontinued due to loss of licenses to participate in the Skype network as peers. In combination these two products made it possible to create roaming cordless mesh networks with robust handoff.

Protocol[edit]

Skype uses a proprietary Internet telephony (VoIP) network called the Skype protocol. The protocol has not been made publicly available by Skype and official applications using the protocol are closed-source. Part of the Skype technology relies on the Global Index P2P protocol belonging to the Joltid Ltd. corporation. The main difference between Skype and standard VoIP clients is that Skype operates on a peer-to-peer model (originally based on the Kazaa software[74]), rather than the more usual client–server model (note that the very popular SIP model of VoIP is also peer-to-peer, but implementation generally requires registration with a server, as does Skype).

As far as networking stack support is concerned, Skype only supports the IPv4 protocol. It lacks support for the next generation Internet protocol, IPv6.[75]

Protocol detection and control[edit]

Many networking and security companies claim to detect and control Skype's protocol for enterprise and carrier applications. While the specific detection methods used by these companies are often private, Pearson's chi-squared test and Naive Bayes classification are two approaches that were published in 2008.[76] Combining statistical measurements of payload properties (such as byte frequencies and initial byte sequences) as well as flow properties (like packet sizes and packet directions) has also shown to be an effective method for identifying Skype's TCP- and UDP-based protocols.[77]

Audio codecs[edit]

G.729 and SVOPC. Skype added a Skype-created codec called SILK to Skype 4.0 for Windows and other Skype clients. SILK is intended to be "lightweight and embeddable".[78]

Video codecs[edit]

VP7 is used for versions prior to Skype 5.5[79][80][81][82][83]

As of version 5.7 VP8 is used for both group and one on one standard definition video chat and H.264 is used for 720p and 1080p high definition group and one on one video chat.[84][85]

Release history[edit]

Windows[edit]

OS X[edit]

Linux[edit]

Android[edit]

Security and privacy[edit]

Skype is claimed initially to be a secure communication, with one of its early web pages stating "highly secure with end-to-end encryption".[100] Security services were invisible to the user, and encryption cannot be disabled. Skype reportedly uses publicly documented, widely trusted encryption techniques: RSA for key negotiation and the Advanced Encryption Standard to encrypt conversations.[101] However, it is impossible to verify that these algorithms are used correctly, completely and at all times as there is no public review possible without a protocol specification and/or the program source code. Skype provides an uncontrolled registration system for users with no proof of identity. Instead, a free choice of nicknames permits users to use the system without revealing their identity to other users. It is trivial to set up an account using any name; the displayed caller's name is no guarantee of authenticity. A third party paper analyzing the security and methodology of Skype was presented at Black Hat Europe 2006. It analyzed Skype and found a number of security issues with the current security model.[102]

Skype incorporates some features, which tend to hide its traffic, but it is not specifically designed to thwart traffic analysis and therefore does not provide anonymous communication. Some researchers have been able to watermark the traffic so that it is identifiable even after passing through an anonymizing network.[103]

In an interview Kurt Sauer, the Chief Security Officer of Skype, said, "We provide a safe communication option. I will not tell you whether we can listen or not."[104] Skype's client uses an undocumented and proprietary protocol. The Free Software Foundation (FSF) is concerned by user privacy issues arising from using proprietary software and protocols and has made a replacement for Skype one of their high priority projects.[105] Security researchers Biondi and Desclaux have speculated that Skype may have a back door, since Skype sends traffic even when it is turned off and because Skype has taken extreme measures to obfuscate their traffic and functioning of their program.[106] Several media sources reported that at a meeting about the "Lawful interception of IP based services" held on 25 June 2008, high-ranking unnamed officials at the Austrian interior ministry said that they could listen in on Skype conversations without problems. Austrian public broadcasting service ORF, citing minutes from the meeting, reported that "the Austrian police are able to listen in on Skype connections". Skype declined to comment on the reports.[107][108] One easily demonstrated method of monitoring is to set up two computers with the same skype userid and password. When a message is typed or a call is received on one computer, the second computer duplicates the audio and text. This requires knowledge of the userid and password.

The United States Federal Communications Commission (FCC) has interpreted the Communications Assistance for Law Enforcement Act (CALEA) as requiring digital phone networks to allow wiretapping if authorized by an FBI warrant, in the same way as other phone services. In February 2009 Skype said that, not being a telephone company owning phone lines, it is exempt from CALEA and similar laws, which regulate US phone companies, and in fact it is not clear whether Skype could support wiretapping even if it wanted to.[109] According to the ACLU, the Act is inconsistent with the original intent of the Fourth Amendment to the U.S. Constitution;[110] more recently, the ACLU has expressed the concern that the FCC interpretation of the Act is incorrect.[111][112] It has been suggested that Microsoft made changes to Skype's infrastructure to ease various wiretapping requirements;[113] however, Skype denies the claims.[114]

Some time before Skype was sold in 2009, the company had started its own program, called Project Chess, to explore legal and technical ways to easily share calls with intelligence agencies and law enforcement.[115]

On 20 February 2009 the European Union's Eurojust agency announced that the Italian Desk at Eurojust would "play a key role in the coordination and cooperation of the investigations on the use of internet telephony systems (VoIP), such as 'Skype'. ... The purpose of Eurojust’s coordination role is to overcome the technical and judicial obstacles to the interception of internet telephony systems, taking into account the various data protection rules and civil rights"[116]

In November 2010, a flaw was disclosed to Skype that showed how hackers could secretly track any user's IP address.[117] As of 2013, this has still not been fixed.[118]

In 2012, Skype introduced automatic updates to better protect users from security risks, but received some challenge from users of the Mac product, as the updates cannot be disabled from version 5.6 on,[119] both on Mac OS and Windows versions, although in the latter, and only from version 5.9 on, automatic updating can be turned off in certain cases.[120]

According to a 2012 Washington Post article, Skype "has expanded its cooperation with law enforcement authorities to make online chats and other user information available to police"; the article additionally mentions Skype made changes to allow authorities access to addresses and credit card numbers.[121]

In November 2012, Skype was reported to have handed over user data of a pro-Wikileaks activist to Dallas, Texas-based private security company iSIGHT Partners without a warrant or court order. The allegation was an apparent breach of Skype's privacy policy. Skype responded with a statement that it launched an internal investigation to probe the breach of user data privacy.[122]

13 November 2012, a Russian user published a flaw in Skype's security, which allowed any person to take over a Skype account knowing only the victim's email by following 7 steps.[123][124] This vulnerability was claimed to exist for months, and existed for more than 12 hours since published widely.

14 May 2013, it was documented that a URL sent via a Skype instant messaging session was usurped by the Skype service and subsequently used in a HTTP HEAD query originating from an IP address registered to Microsoft in Redmond (the IP address used was 65.52.100.214). The Microsoft query used the full URL supplied in the IM conversation, and was generated by a previously undocumented security service.[125] Security experts speculate the action was triggered by a technology similar to Microsoft's SmartScreen Filter used in its browsers.[126]

The 2013 mass surveillance disclosures revealed that agencies such as the NSA and the FBI have the ability to eavesdrop on Skype, including the monitoring and storage of text and video calls and file transfers.[127][128][129] The PRISM surveillance program, which requires FISA court authorization, reportedly has allowed the NSA unfettered access to its data center supernodes. According to the leaked documents, integration work began in November 2010, but it was not until February 2011 that the company was served with a directive to comply signed by the attorney general,[127] with NSA documents showing that collection began on 31 March 2011.[130]

Service in the People's Republic of China[edit]

Since September 2007, users in China trying to download the Skype software client have been redirected to the site of TOM Online, a joint venture between a Chinese wireless operator and Skype, from which a modified Chinese version can be downloaded.[131] The TOM client participates in China's system of Internet censorship, monitoring text messages between Skype users in China as well as messages exchanged with users outside the country.[132][133] Niklas Zennström, then chief executive of Skype, told reporters that TOM "had implemented a text filter, which is what everyone else in that market is doing. Those are the regulations." He also stated: "One thing that’s certain is that those things are in no way jeopardising the privacy or the security of any of the users."[134]

In October 2008, it was reported that TOM had been saving the full message contents of some Skype text conversations on its servers, apparently focusing on conversations containing political issues such as Tibet, Falun Gong, Taiwan independence, and the Chinese Communist Party. The saved messages contain personally identifiable information about the message senders and recipients, including IP addresses, usernames, land line phone numbers, and the entire content of the text messages, including the time and date of each message. Information about Skype users outside China who were communicating with a TOM-Skype user was also saved. A server misconfiguration made these log files accessible to the public for a time.[133][135][136]

Research on the TOM-Skype venture has revealed information about blacklisted keyword checks, allowing censorship and surveillance of its users. The partnership has received much criticism for the latter. Microsoft remains unavailable for comment on the issue. [137]

According to reports from the advocacy group – Great Fire - Microsoft have modified censorship restrictions and ensured encryption of all user information. [138] Furthermore, Microsoft is now partnered with Guangming Founder (GMF) in China. [139]

Localisation[edit]

Skype comes bundled with the following locales and languages: Arabic, Bulgarian, Catalan, Chinese (Traditional and Simplified), Croatian, Czech, Danish, Dutch, Estonian, Finnish, French, German, Greek, Hebrew, Hungarian, Indonesian, Italian, Japanese, Korean, Latvian, Lithuanian, Norwegian, Polish, Portuguese (Brazilian and European), Romanian, Russian, Serbian, Slovak, Slovenian, Spanish, Swedish, Thai, Turkish, Ukrainian and Vietnamese.

As the program (on Windows) offers users the option of creating new language files, at least 31 other (full or partial) localizations are also available for the following languages: Adyghe, Afrikaans, Albanian, Aragonese, Armenian, Basque, Belarusian, Bosnian, Breton, Chuvash, Cornish, Erzya, Esperanto, Faroese, Georgian, Irish, Khmer, Ligurian, Macedonian, Mirandese, Nias, Nynorsk, Palatinate German, Persian, Scottish Gaelic, Tajik, Tamil, Telugu, Uyghur (Persian and Latin script), Welsh[140]

Customer service[edit]

As of February 2012, Skype provides support through their web support portal, support community, @skypesupport on Twitter, and Skype Facebook page. Direct contact via email and live chat is available through their web support portal. Chat Support is a premium feature available to Skype Premium and some other paid users.

In January 2010 Skype rescinded their policy of seizing funds in Skype accounts that have been inactive (no paid call) for 180 days. This was in settlement of a class action lawsuit.[141] Skype also paid up to US$4 to persons who opted into the action.

Skype's refund policy states that they will provide refunds in full if customers have used less than 1 euro of their Skype Credit. "Upon a duly submitted request, Skype will refund you on a pro rata basis for the unused period of a Product".

Skype has come under some criticism from users for the inability to completely close accounts. Users not wanting to continue using Skype can make their account inactive by deleting all personal information, except for the user name.[142]

Educational use[edit]

Although Skype is a commercial product, its free version is being used with increasing frequency among teachers and schools interested in global education projects.[143] For example Skype is being used to facilitate language exchange. Students in different parts of the world are paired off, each is a native speaker of the language that the other wishes to learn. In conversations over Skype they alternate between the two languages.[144][145][146]

Teachers are using Skype in unique ways to fulfill educational goals. The videoconferencing aspect of the software is valuable in that it provides a way to connect students who speak different languages, hold virtual field trips, and reach out to experts in varying fields of study. These experiences allow students a chance to apply what they are learning in the classroom to real-life experiences and it also achieves further learning opportunities.[147][148]

Skype in the classroom is another free tool that Skype has set up on its website. It provides teachers with a way to make their classrooms more interactive and interesting. Skype in the classroom is a service that teachers can sign up for that will allow students to meet other students, talk to experts, and share ideas. Teachers can collaborate with other teachers around the world and design different learning experiences for their students. There are various Skype lessons, in which students can participate. Teachers can also use Skype’s search tool and find experts in the field of their choice.[149]

Outages and downtime[edit]

On 16 August 2007, Skype became unavailable for two days to a majority of its users. Millions of users were requesting to log in at the same time following a routine Windows Update and this flooded the peer-to-peer system.[150]

On 22 December 2010, it was reported that Skype experienced an outage estimated to represent 8 million foregone calls.[151] Skype administrators placed the following message on their Twitter page: "Some of you may have problems signing in to Skype – we're investigating, and we're sorry for the disruption to your conversations...engineers and site operations are working non-stop to get things back to normal."[152][153] The problem came down to the limited availability of "supernodes", affecting some versions of Skype.[154] Later in the day, Skype's CEO, Tony Bates, issued an apology. He said that the matter was being taken very seriously and was being thoroughly investigated. He said that malicious attack was not being ruled out as a problem cause and he put his estimate of the foregone calls at about 10 million.[155] On 23 December 2010, Skype's blog with Tony Bates issued another apology through a video posted on YouTube for the Skype outage.[156]

The problem persisted across the North America, Latin America, Europe and Asia. It had started to subside by 8:30 pm UTC; however users were warned it might take several hours for the program to be fully operative again.[157] It was reported at 9:27 am 23 December UTC that most users were able to log in again although some still could not.[158] On the other hand into Thursday only about a third of the expected traffic was actually using Skype, relative to the time-period.[159] On 23 December 2010, Skype said on its blog that the system had stabilized, and a detailed explanation of the incident was published six days later.[160] Bates offered all Pay As You Go and Pre-Pay customers a free call to any landline as compensation.[161] Subscribers had their subscription extended by one week.

Open source alternatives[edit]

Open source alternatives to Skype include SecureHaze, Jitsi, Ekiga and Vox. These multiplatform clients can encrypt chats, calls and video calls. Users need to register an XMPP account to use some of the software.

See also[edit]

References[edit]

  1. ^ Guzik, Aga (8 April 2014). "Skype for Modern Windows 2.7, with Multiple Ways to Manage Your Availability". Skype Blogs. Microsoft. Retrieved 13 April 2014. 
  2. ^ "Skype". Apps for Windows. Microsoft. Retrieved 13 April 2014. 
  3. ^ Kingwell, Lara (26 February 2014). "Skype for Windows Phone 8: 2.16 – Improved Security with Microsoft Account". Skype Blogs. Microsoft. Retrieved 13 April 2014. 
  4. ^ "Skype". Windows Phone Apps+Games Store. Microsoft. Retrieved 13 April 2014. 
  5. ^ Kocharhook and Huang, Nick and Tom (26 March 2014). "Skype for Mac Version 6.15 – Now Even More Stable (Thanks to YOU!)". Skype Blogs. Microsoft. Retrieved 13 April 2014. 
  6. ^ Ansell, Elaine (13 February 2014). "Skype’s Enhanced Chat Experience". Skype Blogs. Microsoft. Retrieved 13 April 2014. 
  7. ^ "Skype for iPhone". iTunes Preview. Apple Inc. Retrieved 13 April 2014. 
  8. ^ "Skype for iPad". iTunes Preview. Apple Inc. Retrieved 13 April 2014. 
  9. ^ Cimmino, Marco (20 May 2013). "Skype for Linux 4.2". Skype Blogs. Microsoft. Retrieved 13 April 2014. 
  10. ^ a b Lin, Eric (18 March 2014). "Skype 4.7 for Android: Your Battery Is Breathing a Sigh of Relief". Skype Blogs. Microsoft. Retrieved 13 April 2014. 
  11. ^ "Skype". Google Play. Google. Retrieved 13 April 2014. 
  12. ^ Ansell, Elaine (13 February 2014). "Skype’s Enhanced Chat Experience". Skype Blogs. Microsoft. Retrieved 13 April 2014. 
  13. ^ "Skype". BlackBerry World. BlackBerry. Retrieved 13 April 2014. 
  14. ^ "What programming language was Skype originally written in?". Quora. Retrieved 17 December 2013. 
  15. ^ "How can they be so good?": The strange story of Skype, Toivo Tänavsuu, arstechnica, 2013-09-02.
  16. ^ Andreas Thomann (6 September 2006). "Skype – A Baltic Success Story". credit-suisse.com. Retrieved 24 February 2008. 
  17. ^ "Skype grows FY revenues 20%, reaches 663 mln users". 
  18. ^ "Skype employees". 
  19. ^ "http://blogs.skype.com/en/2011/10/acquisitionclose.html". Skype.com. 
  20. ^ "Microsoft confirms takeover of Skype". bbc.com. 10 May 2011. Retrieved 6 November 2012. 
  21. ^ "Bye Bye Skype, Top 3 Free Replacements". Ostatic.com. Retrieved 4 December 2011. 
  22. ^ "More universities banning Skype". 24 September 2006. Retrieved 14 December 2010. 
  23. ^ "Ban Skype". 10 November 2005. Retrieved 14 December 2010. 
  24. ^ "About Skype: What is Skype?". Retrieved 28 July 2010. 
  25. ^ "Skype — A Baltic Success Story". credit-suisse.com. Retrieved 24 February 2008. 
  26. ^ "Happy Birthday Skype: Even monkeys use it now". Emirates 24/7. 28 August 2013. Retrieved 28 August 2013. 
  27. ^ "eBay Completes Acquisition of Skype". eBay. 2005-10-14. Retrieved 2013-04-08. 
  28. ^ a b "Microsoft to acquire Skype". 10 May 2011. Retrieved 10 May 2011. 
  29. ^ Toor, Amar. "Microsoft finalizes acquisition of Skype, Tony Bates shares his thoughts (video)". Engadget. Retrieved 14 October 2011. 
  30. ^ "Microsoft: Windows Live Messenger Retiring, Users Moving to Skype on March 15". Retrieved 2013-02-06. 
  31. ^ Kniskern, Kip (15 February 2013). "Skype news: Messenger shutting down, new Video Messages, and lots of growth". Liveside. Retrieved 17 February 2013. 
  32. ^ "Usernames, aliases and nicknames – your Skype passport". Skype.com. Retrieved 27 August 2009. 
  33. ^ Villu Arak. "Four new SkypeIn countries". Skype Blogs. Retrieved 13 August 2007. 
  34. ^ "Skype.com". Skype.com. Retrieved 10 October 2010. 
  35. ^ "Group video calling". Skype. December 2012. 
  36. ^ "Skype and Emergency Services". 
  37. ^ "Draft Report from TEITAC Task Force on 255/508 differences, with proposals for TEITAC discussion". Retrieved 13 July 2010. 
  38. ^ "Frequently Asked Questions". 911VoIP.org. Retrieved 31 March 2009. 
  39. ^ Ryan Lawler, GigaOm. "Comcast bringing Skype video chat into the living room." 13 June 2011. Retrieved 13 June 2011.
  40. ^ "Skype video messaging officially launches on Windows, Mac, iOS, Android -- but not Windows Phone". 17 June 2013. 
  41. ^ "Skype app for iPhone/iPad updated to HD". 12 August 2013. 
  42. ^ "eBay Inc. reports third quarter 2006 results" (PDF). 
  43. ^ "eBay Inc. reports first quarter 2007 results" (PDF). 
  44. ^ "eBay Inc. reports first quarter 2008 results" (PDF). 
  45. ^ "Skype is the limit thanks to recession". Retrieved 6 January 2009. 
  46. ^ a b "Skype facts Q1 2011". 
  47. ^ "Skype fast facts Q4 2008" (PDF). 
  48. ^ "Skype S.à r.l. SEC filing". 4 March 2011. Retrieved 26 May 2011. 
  49. ^ "Skype users online now". 
  50. ^ "WSJ: Microsoft to buy Skype for $7bn. Rest of world: for real?". ArsTechnica. 10 May 2011. Retrieved 10 May 2011. 
  51. ^ "Skype’s changing traffic growth". Financial Times. 10 May 2011. Retrieved 10 May 2011. 
  52. ^ a b "Skype by the Numbers: It's really Big". Retrieved 1 July 2011. 
  53. ^ a b Ricknäs, Mikael (25 March 2009). "Skype is largest international voice carrier, says study". Network World. IDG News Service. 
  54. ^ a b "International carriers' traffic grows despite Skype popularity". TeleGeography Report and Database. Retrieved 7 December 2006. 
  55. ^ "Skype Commands 13 Percent of International Phone Calls". The Inquisitr. 3 May 2010. Retrieved 4 May 2010. 
  56. ^ "The Bell Tolls for Telcos?". Telegeography. 13 Feb 2013. Retrieved 25 March 2013. 
  57. ^ "Skype Hits New Record of 27 Million Simultaneous Users". Retrieved 11 January 2011. 
  58. ^ "29 million people online on Skype". Retrieved 23 February 2011. 
  59. ^ "30 million people online on Skype". Retrieved 28 March 2011. 
  60. ^ "Skype reaches new milestone with 32 million users". Retrieved 26 February 2012. 
  61. ^ "35 Million People Concurrently Online on Skype". Retrieved 8 March 2012. 
  62. ^ "50 million concurrent users online". Retrieved 25 March 2013. 
  63. ^ "More than 70 Million downloads on an Android device". Retrieved 26 June 2012. 
  64. ^ "How’s Skype Doing at MSFT? Usage Jumps 50 %, Users Logged 115B Minutes of Calls Last Quarter". Retrieved 21 July 2012. 
  65. ^ "3 Skypephone Delivers Free Skype to Skype Mobile Calls and Instant Messages at the Touch of a Button". 29 October 2007. 
  66. ^ "NETGEAR Skype WiFi Phone". voipyeah.com. 
  67. ^ "Skype Expands Mobile Strategy at 2008 International CES". Retrieved 7 January 2008. 
  68. ^ "Playstationlifestyle.net". Playstationlifestyle.net. Retrieved 10 October 2010. 
  69. ^ "Skype for Samsung Smart TV". Retrieved 12 February 2013. 
  70. ^ "Skype camera accessory for Samsung Smart TV". Retrieved 12 February 2013. 
  71. ^ "Skype – The Big Blog – Fring's misuse of Skype software was damaging to our brand and reputation". Retrieved 3 August 2010. 
  72. ^ "What the Skype/Nimbuzz Breakup Means To You". Retrieved 25 October 2010. 
  73. ^ "Phone Systems to Power Your Business – Sfa_faq – Digium® The Asterisk Company". Digium.com. Retrieved 4 December 2011. 
  74. ^ "StreamCast sues Kazaa, Skype: here's my take". Blogs.zdnet.com. 27 March 2006. Retrieved 31 March 2009. 
  75. ^ "Skype does not support IPv6.". Skype official Twitter account. 1 November 2012. Retrieved 4 November 2012. 
  76. ^ "Dario Bonfiglio et al. "Revealing Skype Traffic: When Randomness Plays with You", ACM SIGCOMM Computer Communication Review, Volume 37:4 (SIGCOMM 2007), p. 37-48". Dpacket.org. 30 May 2008. Retrieved 31 March 2009. 
  77. ^ Hjelmvik, Erik; John, Wolfgang (27 July 2010). "Breaking and Improving Protocol Obfuscation". ISSN 1652-926X. 
  78. ^ "Skype's new super wideband codec". Wirevolution.com. 13 January 2009. Retrieved 31 March 2009. 
  79. ^ "On2 Technologies Codec Offers High Quality Video to Skype". Archived from the original on 4 December 2007. 
  80. ^ "Skype adds On2 Technologies TrueMotion VP7". 16 November 2007. Retrieved 9 August 2011. 
  81. ^ "Skype goes VP8, embraces open video codec". 3 August 2011. Retrieved 9 August 2011. 
  82. ^ "One-to-One VP8 Video Calling Now Supported in Skype". 3 August 2011. Retrieved 9 August 2011. 
  83. ^ "Skype moves to VP8 for all video calls". The H. 4 August 2011. Archived from the original on 23 May 2012. Retrieved 9 August 2011. 
  84. ^ Jodi Mau (9 January 2012). "Skype – The Big Blog – See and Talk to Your Friends on Skype in Full-HD 1080p with the New Logitech HD Pro Webcam C920". Blogs.skype.com. Retrieved 24 February 2012. 
  85. ^ "Reveal the real you with the Logitech® HD Pro Webcam C920". Blog.Logitech. 5 January 2012. Retrieved 24 February 2012. 
  86. ^ Liive, Raul (2012-10-24). "Skype 6.0 for Mac and Windows Desktop – - Skype Blogs". Blogs.skype.com. Retrieved 2013-06-27. 
  87. ^ Liive, Raul (2012-11-15). "Skype 6.0 for Windows Desktop Update – - Skype Blogs". Blogs.skype.com. Retrieved 2013-06-27. 
  88. ^ "Lync Federation will continue as Windows Live Messenger transitions to Skype - Lync Team Blog - Site Home - TechNet Blogs". Blogs.technet.com. 2012-11-09. Retrieved 2013-06-27. 
  89. ^ by piero. "Skype 6.1 for Windows Desktop with Outlook Integration – - Skype Blogs". Blogs.skype.com. Retrieved 2013-06-27. 
  90. ^ "What’s new in Skype 6.5 for Windows desktop?". Support.skype.com. 2013-06-20. Retrieved 2013-06-27. 
  91. ^ Liive, Raul (2013-03-14). "Skype 6.3 for Windows – - Skype Blogs". Blogs.skype.com. Retrieved 2013-06-27. 
  92. ^ "CREATOR and MASTER cannot edit or remove messages". 
  93. ^ "Bring back the ability of CREATORs/MASTERs to edit/remove chat participants' messages". 
  94. ^ Guzik, Aga. "Skype for Windows Desktop 6.5 with Easier Ways to Share and Add Contacts – - Skype Blogs". Blogs.skype.com. Retrieved 2013-06-27. 
  95. ^ Skype VoIP Software Released For Linux – Slashdot
  96. ^ Skype for Linux blog – Skype 4.0 for Linux
  97. ^ Skype Garage blog – Hotfix for multiple Skype clients
  98. ^ Skype for Linux blog – Skype 4.1 for Linux
  99. ^ Skype for Linux 4.2
  100. ^ "Skype (Wayback Machine Archive)". Archived from the original on 1 July 2004. Retrieved 20 May 2013. 
  101. ^ "Skype Privacy FAQ". Skype. Retrieved 5 December 2006. 
  102. ^ Philippe Biondi and Fabrice Desclaux. "Silver Needle in the Skype" (PDF). blackhat. Retrieved 2 March 2006. 
  103. ^ "George Mason University" (PDF). Retrieved 10 October 2010. 
  104. ^ ZDNet.de. "Telefonieren übers Internet: Wie sicher ist Skype wirklich? – Telekommunikation | Mobile Business". ZDNet.de. Retrieved 31 March 2009. 
  105. ^ "FSF High Priority Projects", Free Software Foundation. Retrieved 26 January 2009.
  106. ^ Biondi P., Desclaux F (2 March 2006 to 3 March 2006). "Silver Needle in the Skype". EADS Corporate Research Center. Retrieved 26 January 2009. 
  107. ^ Sokolov, David AJ (24 July 2008). "Speculation over back door in Skype". Heise Security UK. Archived from the original on 13 July 2010. Retrieved 26 January 2009. 
  108. ^ Leyde, John (24 July 2008). "Austrian official fuels Skype backdoor rumours". The Register UK. Retrieved 29 January 2009. 
  109. ^ "Skype Secrecy Under Attack Again". VoIP News. 24 February 2009. Retrieved 10 October 2010. 
  110. ^ "Big Brother in the Wires: Wiretapping in the Digital Age". ACLU. Retrieved 23 March 2009. 
  111. ^ "CALEA feature page". ACLU. Retrieved 23 March 2009. 
  112. ^ "German Authorities Raiding Homes To Find Skype Tapping Whistleblower". Techdirt. 18 September 2008. Retrieved 31 March 2009. 
  113. ^ Was Skype reworked by Microsoft to make it easier to wiretap? | ITworld
  114. ^ "What Does Skype's Architecture Do?". 26 July 2012. Retrieved 20 May 2013. 
  115. ^ Risen, James; Nick Wingfield (19 June 2013). "Web’s Reach Binds N.S.A. and Silicon Valley Leaders". The New York Times. Retrieved 29 October 2013. 
  116. ^ "Press release: Eurojust coordinates internet telephony". Eurojust.europa.eu. 20 February 2009. Retrieved 10 October 2010. 
  117. ^ "Skype Knew of Security Flaw Since November 2010, Researchers say". 
  118. ^ "Privacy 101: Skype Leaks Your Location". 
  119. ^ "Skype 5.6 for Mac". 
  120. ^ "Skype 5.9 for Windows". 
  121. ^ Skype makes chats and user data more available to police | Washington Post
  122. ^ Gallagher, Ryan (9 November 2012). "Did Skype Give a Private Company Data on Teen WikiLeaks Supporter Without a Warrant?". Slate. Retrieved 11 November 2012. 
  123. ^ "Skype accounts can be hacked with an email address". 
  124. ^ "Уязвимость в skype, позволяющая угнать любой аккаунт". 
  125. ^ "Skype with Care – Microsoft is Reading Everything You Write". Heise Security. 14 May 2013. Archived from the original on 26 December 2013. Retrieved 20 May 2013. 
  126. ^ Adam Back (16 May 2013). "[cryptography] skype backdoor confirmation". Retrieved 20 May 2013. 
  127. ^ a b "How Microsoft handed the NSA access to encrypted messages | World news". The Guardian. Retrieved 2013-07-20. 
  128. ^ Leo Laporte, Steve Gibson (17 July 2013). "Security Now, episode 413". http://twit.tv/sn (Podcast). TWiT. Retrieved 17 July 2013. 
  129. ^ McCarthy, Tom (7 June 2013). "Obama defends secret NSA surveillance programs - as it happened". The Guardian. Retrieved 2013-06-09. 
  130. ^ Prism slide 5.jpg
  131. ^ "Dynamic Internet Technology Inc. Alleges Skype Redirects Users in China to Censorware Version — Ten Days After Users Are Able To Download Freegate Software Through Skype". Archived from the original on 15 January 2008. , TMCnet, 24 September 2007
  132. ^ "Surveillance of Skype messages found in China". International Herald Tribune. 2 October 2008. 
  133. ^ a b Claburn, Thomas (2 October 2008). "Skype Defends VoIP IM Monitoring in China". InformationWeek. 
  134. ^ "Skype says texts are censored by China". FT.com (Financial Times). 18 April 2006. Archived from the original on 23 March 2009. 
  135. ^ Fowler, Geoffrey A.; Jason Dean (3 October 2008). "Skype's China Practices Draw Ire: Joint Venture's Tracking of Text Messages Adds Impetus to Web Code of Conduct". The Wall Street Journal. 
  136. ^ Markoff, John (1 October 2008). "Huge System for Web Surveillance Discovered in China". NYTimes.com. 
  137. ^ "Microsoft blocks censorship of Skype in China: advocacy group". reuters.com (Reuters). 27 November 2013. 
  138. ^ "Microsoft blocks censorship of Skype in China: advocacy group". reuters.com (Reuters). 27 November 2013. 
  139. ^ "A new relationship for a better experience in China". blog.skype.com (Skype). 25 November 2013. 
  140. ^ SkypeInYourLanguage
  141. ^ Ali, Sarmad (14 January 2010). "WSJ". The Wall Street Journal. 
  142. ^ http://en.kioskea.net/faq/30642-how-to-delete-a-skype-account
  143. ^ Branzburg, Jeffrey (March 2007). "Talk Is Cheap: Skype Can Make VoIP a Very Real Communication Option for Your School". Technology & Learning, v27 n8 p36. Retrieved 10 May 2011. 
  144. ^ Language Magazine article
  145. ^ LinguaeLive.ca
  146. ^ the language exchange
  147. ^ Quillen, Ian (4 Feb 2011). "Educators Move Beyond the Hype Over Skype". Education Week. Retrieved 2013-06-09. 
  148. ^ Video Conferencing with Skype
  149. ^ education.skype.com
  150. ^ Arak, V (20 August 2007). "What happened on 16 August". Heartbeat.skype.com. Retrieved 22 December 2010. 
  151. ^ Rooney, B. (22 December 2010). "Skype Outage Hits Users Worldwide". The Wall Street Journal. Retrieved 22 December 2010. 
  152. ^ "Skype outage: millions affected worldwide". Fox News. 22 December 2010. Retrieved 22 December 2010. 
  153. ^ "The original message". Twitter. 22 December 2010. 
  154. ^ Metz, C. (22 December 2010). "Skype goes tits up across globe: Mass supernode death". The Register. Retrieved 22 December 2010. 
  155. ^ Shiels, M. (22 December 2010). "Skype apologises for losing half of daily call traffic". BBC News. Retrieved 22 December 2010. 
  156. ^ Skype — The Big Blog (23 December 2010). "A further update on the Skype downtime". Skype Blogs. Retrieved 23 December 2010. 
  157. ^ Ando, R (22 December 2010). "Update 2-Outage takes out Skype, recovery taking hours". Reuters. Retrieved 23 December 2010. 
  158. ^ Farrell, Nick (23 December 2010). "Skype comes up with 'leaves on the line' excuse". The Inquirer. Retrieved 23 December 2010. 
  159. ^ Johnson, L. (23 December 2010). "Skype issues continue as two thirds of users remain offline". T3.com. Retrieved 23 December 2010. 
  160. ^ "CIO update: Post-mortem on the Skype outage". 29 December 2010. Retrieved 31 December 2010. 
  161. ^ "Skype makes wobbly return, offers compo to paying punters". 24 December 2010. Retrieved 24 December 2010. 
  162. ^ "12 Best Skype Alternatives For VoIP, Video Calls and Conferencing". thetecnica. Retrieved 4 March 2014. 


Further reading[edit]

External links[edit]