|Developer(s)||Twitter Inc. (2011–)
Iain Dodsworth (2008–2011)
|Initial release||July 4, 2008|
|Platform||Chrome Web Store, Mac OS X|
Like other Twitter applications it interfaces with the Twitter API to allow users to send and receive tweets and view profiles. It was the most popular Twitter application with a 23% market share as of June 2010, following only the official Twitter website with 45.7% share for posting new status updates.
TweetDeck consists of a series of customisable columns, which can be set up to display the user's Twitter timeline, mentions, direct messages, lists, trends, favorites, search results, hashtags, or all tweets by or to a single user. The client uses Twitter's own automatic and invisible URL shortening whereby a link of any length will only use 23 characters of a Tweet's 140-character limit. All columns can be filtered to include or exclude words or tweets from users. Tweets can be sent immediately or scheduled for later delivery.
Users can monitor and tweet from multiple accounts simultaneously. For added account security, users signing in with their Twitter username and password can use Twitter's own two-step verification, known to Twitter users as Login Verification.
As of May 2015, TweetDeck added a “confirmation step” feature giving users the option to require an extra step before sending a tweet. 
June 19, 2009 – iPhone version released
May 2010 – iPad version released
October 2010 – Android version made available after a public beta period.
May 25, 2011 – Twitter acquired TweetDeck
September 15, 2011 – TweetDeck tweeted that new updates for all of its versions would be released and that "As part of the process of making TweetDeck more consistent with Twitter.com & Twitter's mobile apps, we're removing deck.ly from our apps." Many users expressed their anger at this feature removal in the comments on the iOS and Android Market. Deck.ly previously allowed users to post tweets in excess of 140 characters.
December 8, 2011 – Twitter released a new version branded "TweetDeck by Twitter", as part of Twitter's redesign of its services. TweetDeck changed from an Adobe AIR application to a native Windows and Mac OS X application in this release, and also introduced a web version of TweetDeck for WebKit-based browsers based on TweetDeck's existing Google Chrome app. The update dropped support for LinkedIn, Google Buzz, Foursquare, MySpace accounts.
March 4, 2013 – TweetDeck announced in a blog post that they would be suspending mobile versions of TweetDeck including TweetDeck AIR, TweetDeck for iPhone and TweetDeck for Android, which will be removed from their respective app stores this May. TweetDeck said they would "focus our development efforts on our modern, web-based versions".
May 2, 2013 – users were informed that 'Facebook is no longer supported in TweetDeck', and that on May 7, Facebook accounts and Facebook columns will be removed.
July 25, 2013 – at 12:00 PM EDT US, Twitter turned off API v1 which effectively shut down the Android, iOS, and AIR versions of TweetDeck.
December 11, 2013 – Twitter started allowing new TweetDeck users to sign in with their Twitter usernames and passwords, removing the barrier-to-entry which had previously existed in requiring users to register a separate TweetDeck account. In a blog post, Twitter said "When single sign in is fully available to all current users, we’ll also make it possible to seamlessly integrate your current TweetDeck settings and preferences"
Originally, as it is now, TweetDeck was aimed towards the Twitter social networking service. Over the years, TweetDeck introduced support for other social networks, but has since removed that support.
On March 16, 2009, a pre-release version was released featuring Facebook status updates integration. As of April 8, 2009, Facebook status updates were part of the standard program. From version 0.30 TweetDeck also supported MySpace integration. Version 0.32, released on November 30, 2009, added LinkedIn integration and new Twitter features. In May 2010 TweetDeck also added integration with the Google Buzz and Foursquare social networks.
In 2012 TweetDeck reverted to only supporting Twitter and Facebook, ending support for LinkedIn, MySpace, and the now defunct Google Buzz effective June 2012.
In May 2013, TweetDeck removed support for Facebook accounts, becoming focused once again on the core Twitter experience.
TweetDeck Ltd (company)
A year after launching TweetDeck in 2008, Iain Dodsworth received his initial $300,000 seed funding from The Accelerator Group, Howard Lindzon, Taavet Hinrikus, Gerry Campbell, Roger Ehrenberg, betaworks, Brian Pokorny, and Bill Tai. The company raised a Series A round of funding with many of these same investors, and Ron Conway, Danny Rimer, and the SV Angel group.
On January 22, 2013, The American directors of Twitter were sent a letter by Companies House (the United Kingdom Registrar of Companies) warning them that their UK subsidiary company TweetDeck Ltd. was at risk of closure, over missed accounting deadlines. This had no bearing on the product or service which was by then run by Twitter, not by TweetDeck Ltd.
The letter stated: "The Registrar of Companies gives notice that, unless cause is shown to the contrary, at the expiration of 3 months from the above date the name of TweetDeck Ltd will be struck off the register and the company will be dissolved." 
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- "Twitter buys UK's TweetDeck for £25m". The Guardian. 27 May 2011.
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- "TweetDeck: Twitter's UK Firm Shut By Regulator". Sky news. Retrieved 7 May 2013.
- "Twitter is shutting down TweetDeck for Windows on April 15th | The Verge". Retrieved 17 March 2016.
- "Twitter to End Support of TweetDeck App for Windows - Fortune". Retrieved 17 March 2016.