Business models for open-source software
||It has been suggested that Open-source software#Funding be merged into this article. (Discuss) Proposed since December 2013.|
||This article duplicates, in whole or part, the scope of other article(s) or section(s), specifically, Open-source software#Funding. (December 2013)|
Open-source software is widely used for public and non-commercial applications. In addition, many independent software vendors (ISVs), value-added resellers (VARs), and hardware vendors (OEMs or ODMs) use open-source frameworks, modules, and libraries inside their proprietary, for-profit products and services. From the customer's perspective, the ability to use open-source technology under standard commercial terms and support is valuable. Customers are willing to pay for the legal protection (e.g., indemnification from intellectual property infringement), "commercial-grade QA," and professional support/training/consulting that are typical of commercial software built on top of the innovation and independence that comes with open source.
- 1 Challenges
- 2 Approaches
- 2.1 Dual-licensing
- 2.2 Selling professional services
- 2.3 Selling of branded merchandise
- 2.4 Selling software as a service
- 2.5 Partnership with funding organizations
- 2.6 Voluntary donations
- 2.7 Bounties
- 2.8 Pre-order/crowdfunding/reverse-bounty model
- 2.9 Advertising-supported software
- 2.10 Selling of optional proprietary extensions
- 2.11 Selling of required proprietary parts of a software product
- 2.12 Re-licensing under a proprietary license
- 2.13 Obfuscation of source code
- 2.14 Delayed open-sourcing
- 3 FOSS and economy
- 4 Examples
- 5 See also
- 6 Further reading
- 7 References
||This article or section may need to be cleaned up. It has been merged from Commercial open-source applications.|
|This section needs additional citations for verification. (December 2013)|
Open-source software can be sold and used in general commercially. Also, commercial open-source applications are a part of the software industry for some time. Despite that, except for Red Hat and VA Software, no other pure open-source company has gone public on the major stock markets. While commercialization or funding of open-source software projects is possible, it is considered challenging.
Since several open-source licenses stipulate that derived works must distribute their intellectual property under an open-source (copyleft) license, ISVs and VARs have to develop new legal and technical mechanisms to foster their commercial goals, as many traditional mechanisms are not directly applicable anymore.
Traditional business wisdom suggests that a company's methods, assets, and intellectual properties should remain concealed from market competitors as long as possible to maximize the profitable commercialization time of a new product.[according to whom?] Open-source software development minimizes the effectiveness of this tactic; development of the product is usually performed in view of the public, allowing competing projects or clones to incorporate new features or improvements as soon as the public code repository is updated, as permitted by most open-source licenses. Also in the computer hardware domain, a hardware producer who provides free and open software drivers reveals the knowledge about hardware implementation details to competitors, who might use this knowledge to catch up.
Therefore, there is considerable debate about whether vendors can make a sustainable business from an open-source strategy. In terms of a traditional software company, this is probably the wrong question to ask. Looking at the landscape of open source applications, many of the larger ones are sponsored (and largely written) by system companies such as IBM who may not have an objective of software license revenues. Other software companies, such as Oracle and Google, have sponsored or delivered significant open-source code bases. These firms' motivation tends to be more strategic, in the sense that they are trying to change the rules of a marketplace and reduce the influence of vendors such as Microsoft. Smaller vendors doing open-source work maybe be less concerned with immediate revenue growth than developing a large and loyal community, which may be the basis of a corporate valuation at merger time.
A variety of open-source compatible business approaches have gained prominence in recent years[according to whom?]; notable examples include dual licensing, software as a service, not charging for the software but for services, freemium, donation-based funding, and crowdfunding (see the Approaches section, below).
The underlying objective of these business models is to harness the size and international scope of the open-source community (typically more than an order of magnitude larger than what would be achieved with closed-source models) for a sustainable commercial venture. The vast majority of commercial open-source companies experience a conversion ratio (as measured by the percentage of downloaders who buy something) well below 1%, so low-cost and highly-scalable marketing and sales functions are key to these firms' profitability.
There are several different types of business models for making profit using open-source software (OSS) or funding the creation. Below are existing and legal commercial business approaches in context of open-source software and open-source licenses. The acceptance of these approaches varies; some of these approaches are recommended (like selling services), others are accepted, while still others are considered controversial or even unethical by the open-source community.
Dual licensing offers the software under an open-source license but also under separate proprietary license terms. The proprietary version can be sold to finance the continued development of the free open-source version. Customers can be attracted to a no-cost and open-source edition, then be part of an up-sell to a commercial enterprise edition. Further, customers will learn of open-source software in a company's portfolio and offerings but generate business in other proprietary products and solutions, including commercial technical support contracts and services. A popular example is the MySQL database which is dual-licensed under a commercial proprietary license as also under the GPLv2 by Oracle. Another example is the Sleepycat License.
Selling professional services
||It has been suggested that Professional open source be merged into this article. (Discuss) Proposed since December 2013.|
Another possibility is offering open-source software in source code form only, while providing executable binaries to paying customers only, offering the commercial service of compiling and packaging of the software. Also, providing goods like physical installation media (e.g. DVDs) can be a commercial service.
Selling of branded merchandise
Some open-source organizations, for instance Mozilla Foundation or the Wikimedia Foundation, try to sell branded merchandise articles (e.g. t-shirts, coffee mugs). This can be also seen as an additional service to the user community.
Selling software as a service
Selling subscriptions for online accounts and server access to customers is a way of making profit based on open-source software. Also, combining desktop software with a service, called software plus services. Providing cloud computing services or software as a service (SaaS) without the release of the open-source software itself, neither in binary nor in source form, conforms with most open-source licenses (with exception of the AGPL).
While legal, Richard Stallman calls SaaS "inherently bad" as the software freedoms are not given. The FSF called the server-side use-case without release of the source-code the ASP loophole in the GPLv2 and encourage therefore the use of the Affero General Public License which plugged this hole in 2002. In 2007 the FSF contemplated about including the special provision of AGPLv1 into GPLv3 but ultimately decided to keep the licenses separated.
Partnership with funding organizations
Other financial situations include partnerships with other companies. Governments, universities, companies or other non-governmental organizations may develop internally or hire a contractor for custom in-house modifications to software, then release that code under an open-source license. Some organizations support the development of open source software by grants or stipends, like Google with the Summer of Code initiative founded in 2005.
Also, there were experiments by Independent developers to fund development of open-source software donation-driven directly by the users, e.g. with the Illumination Software Creator in 2012. SourceForge, for example, lets users donate money to hosted projects which have chosen to accept donations. The arrival of Internet micro-payments systems in the 2000s like PayPal, flattr and Bitcoin is helping this approach.
Also, bigger donation campaigns exist. For instance, in 2004 the Mozilla Foundation had a fundraising campaign to support the launch of the Firefox 1.0 web browser. A two-page ad in the December 16 edition of the New York Times, placed by Mozilla Foundation in coordination with Spread Firefox, featured the names of the thousands of people worldwide who donated to the campaign.
The users of a particular software artifact may come together and pool money into an open-source bounty for the implementation of a desired feature or functionality. Offered bounties as funding approach exists since some time, for instance Bountysource is web platform which offers this funding model for open source software since 2003.
Another bounty source are companies or foundations who set up bounty programs for implemented features or bugfixes in open source software which has a relevance to them. For instance, freelancing open source programmers are funded and paid by the Mozilla for security bug hunting and fixing via a bounty program since 2004.
A newer funding opportunity for open-source software projects is crowdfunding, which shares similarities with the pre-order or Praenumeration business model, as well as the reverse bounty model. It is typically organized over web platforms like Kickstarter, Indiegogo, Catincan, or Bountysource (see also Comparison of crowd funding services). An example is a successful funded Indiegogo campaign of the Australian programer Timothy Arceri who offered for $2500 to implement in two weeks a OpenGL 4.3 extension for the Mesa library.
In order to commercialize FOSS, many companies (including Google, Mozilla, and Ubuntu) have moved towards an economic model of advertising-supported software. For instance, the open-source application AdBlock Plus gets paid by Google for letting whitelisted Acceptable Ads bypassing the browser ad remover. As another example is SourceForge, an open-source project service provider, has the revenue model of advertising banner sales on their website. In 2006, Sourceforge Inc reported quarterly takings of USD$6.5 million and $23 million in 2009.
Selling of optional proprietary extensions
Some companies sell proprietary but optional extensions, modules, plugins or add-ons to an open-source software product. This can be a "license conform" approach with many open-source licenses if done technically sufficiently carefully. For instance, mixing proprietary code and open-source licensed code in statically linked libraries or compiling all source code together in a software product might violate open-source licenses, while keeping them separated by interfaces and dynamic-link libraries might often adhere to license conform.
This approach is a variant of the freemium business model. The proprietary software may be intended to let customers get more value out of their data, infrastructure, or platform, e.g. operate their infrastructure/ platform more effectively and efficiently, manage it better, or secure it better. Examples include the IBM proprietary Linux software, where IBM contributes to the Linux open source ecosystem, but it builds and delivers (to IBM’s paying customers) database software, middleware and other software that runs on top of the open-source core. Other examples of proprietary products built on top of open source software include Red Hat Enterprise Linux and Cloudera's Apache Hadoop-based software. Some companies appear to re-invest a portion of their financial profits from the sale of proprietary software back into the open source infrastructure.
Selling of required proprietary parts of a software product
A variant of the approach above is the keeping of required data content (for instance a video game's audio, graphic and other art assets) of a software product proprietary while making the software's source code open-source. While this approach is completely legitimate and compatible with most open-source licenses, customers have to buy the content to have a complete and working software product. Restrictive licenses can then be applied on the content, which prevents the redistribution or re-selling of the complete software product. An example is Kot-in-Action Creative Artel video game Steel Storm, where the engine is licensed as GPLv2 while the artwork is CC-BY-NC-SA 3.0 licensed. Doing so conforms with the FSF and Richard Stallman, who stated that for art or entertainment the software freedoms are not required or important.
The similar product bundling of an open-source software product with a proprietary hardware part is called tivoization and legal with most open-source licenses except GPLv3, which explicitly prohibits this use-case.
Re-licensing under a proprietary license
If a software product uses only own software and open-source software under a Permissive free software licence, a company can re-license the resulting software product under a proprietary license and sell the product without the source code or software freedoms. For instance, Apple Inc. is avid user of this approach by using source code and software from various open-source projects, e.g. the BSD Unix operating system kernel under the BSD license was a used in the Mac PCs which are sold as proprietary products.
Obfuscation of source code
An approach to allow commercialization under some open-source licenses while still protecting crucial business secrets, intellectual property and technical know-how is obfuscation of source code. This approach was used in several cases, for instance by Nvidia in their open-source graphic card device drivers. This practise is used to get the open-source-friendly propaganda without bearing the inconveniences, and there has been debate in the free-software/open-source community on whether it is illegal to skirt copyleft software licenses by releasing source code in obfuscated form, such as in cases in which the author is less willing to make the source code available. The general consensus was that while unethical, it was not considered a violation. One of the alterations made to the GNU General Public License in version 3 was to require that the "preferred" version of the source code has to be made available, which was inserted to prevent the release of obfuscated source code.
Some companies provide the latest version available only to paying customers. A vendor forks a non-copyleft software project then adds closed-source additions to it and sells the resulting software. After a fixed time period the patches are released back upstream under the same license as the rest of the codebase. This business model is called version lagging or time delaying.
A extreme variant of "time-delayed open-sourcing" is a business practice popularized by Id Software and 3D Realms who released several of their software products under a free software license after a long proprietary commercialization time period and the return of investment was achieved. The motivation of companies following this practice of releasing the source code when a software reaches the commercial end-of-life, is to prevent that their software becomes unsupported Abandonware or even get lost due to Digital obsolescence. This gives the user communities the chance to continue development and support of the software product themself as open-source software project. Many examples from the video game domain are in the List of commercial video games with later released source code.
Popular non-game software examples are the Netscape Communicator which was open sourced 1998 and the office suite StarOffice which was released by Sun Microsystems in October 2000 on their commercial end of life. Both releases became the base of important open-source projects, namely the Mozilla Firefox and OpenOffice.org/LibreOffice.
This approach works only with own source code or with software under specific open-source licenses, namely the permissive licences, as there is no copy-left license available which allows the opening of source-code in a defined delayed time-window after distributing or selling of a software product.
FOSS and economy
According to Yochai Benkler, Jack N. and Lillian R. Berkman Professor for Entrepreneurial Legal Studies at Harvard Law School, free software is the most visible part of a new economy of commons-based peer production of information, knowledge, and culture. As examples, he cites a variety of FOSS projects, including both free software and open source.
This new economy is already under development. In order to commercialize FOSS, many companies, Google being the most successful, are moving towards an economic model of advertising-supported software. In such a model, the only way to increase revenue is to make the advertising more valuable. Facebook has recently come under fire for using novel user tracking methods to accomplish this.
|It has been suggested that portions of this section be moved into List of commercial open-source applications. (Discuss)|
Much of the Internet runs on open-source software tools and utilities such as Linux, Apache, MySQL, and PHP, known as the LAMP stack for web servers. Using open source appeals to software developers for three main reasons: low or no cost, access to source code they can tailor themselves, and a shared community that ensures a generally robust code base, with quick fixes for any new issues that surface.
Despite doing much business in proprietary software, some companies like Oracle Corporation and IBM participated in developing free and open-source software to deter from monopolies and take a portion of market share for themselves. See Commercial open-source applications for the list of current commercial open-source offerings. Netscape's actions were an example of this, and thus Mozilla Firefox has become more popular, getting market share from Internet Explorer.
- Active Agenda is offered for free, but requires all extensions to be shared back with the world community. The project sells a "Non-Reciprocal Private License" to anyone interested in keeping module extensions private.
- Adobe Systems offers Flex for free, while selling the Flash Builder IDE.
- Apple Inc. offers Darwin for free, while selling Mac OS X.
- Asterisk (PBX), digital electronics hardware controlled by open-source software
- Codeweavers sells CrossOver commercially, deriving it from the free Wine project they also back.
- Canonical Ltd. offers Ubuntu for free, while they sell commercial technical support contracts.
- Cloudera's Apache Hadoop-based software.
- Francisco Burzi offers PHP-Nuke for free, but the latest version is offered commercially.
- DaDaBIK, although following a donationware approach, requires a small, minimum donation fee, to be downloaded.
- IBM proprietary Linux software, where IBM delivers database software, middleware and other software.
- Ingres is offered for free, but services & support are offered as part of a subscription. The Ingres Icebreaker Appliance is also offered as a commercial database appliance.
- id Software releases their legacy game engines under the GPL, while retaining proprietary ownership on their latest incarnation.
- Mozilla Foundation have a partnership with Google and other companies which provides revenue for inclusion of search engines in Mozilla Firefox.
- MySQL is offered for free, but with the enterprise version includes support and additional features.
- Novell offers openSUSE for free through the openSUSE Project, while selling SUSE Linux Enterprise (SLE).
- OpenSearchServer offers its community edition on SourceForge and an enterprise edition with professional services to enterprises with a paid license
- Oracle - VirtualBox is free and open-source to anyone, but the VirtualBox extension pack can only be used for free at home, therefore requiring payment for business
- Red Hat sells support subscriptions for Red Hat Enterprise Linux (RHEL) which is an enterprise distribution periodically forked from the community-developed Fedora.
- Sourcefire offers Snort for free, while selling Sourcefire 3D.
- Sun Microsystems (acquired by Oracle in 2010) once offered OpenOffice.org for free, while selling StarOffice.
- Untangle provides its Lite Package for free, while selling its Standard and Premium Packages by subscription.
- Zend Technologies offers Zend Server CE and Zend Framework for free, but sells Zend Server with support and additional features.
- Free-Libre / Open Source Software (FLOSS) is Commercial Software, David A. Wheeler
- Selling Free Software, Free Software Foundation
- The Emerging Economic Paradigm of Open Source - Bruce Perens (3 October 2005)
- Economic aspects and business models of Free Software - Free Technology Academy (2010)
- FOSS Business Models in Developing countries - compilation of material and sources (2011, archived)
- From Open Source to long-term sustainability: Review of Business Models and Case studies Chang, Victor, Mills, Hugo and Newhouse, Steven (2007)
- The Business and Economics of Linux and Open Source (2003) by Martin Fink (ISBN 0-13-047677-3)
- The Five Open Source Business Models
- collection of articles
- Open source business models, Chapter 2 in Bernard Golden (2005), Succeeding with Open Source, Addison-Wesley, 242 pp. 
- Wikinomics: How Mass Collaboration Changes Everything by Don Tapscott and Anthony D. Williams
- Karl M. Popp and Ralf Meyer (2010). Profit from Software Ecosystems: Business Models, Ecosystems and Partnerships in the Software Industry. Norderstedt, Germany: BOD. ISBN 3-8391-6983-6.
- Wheeler, David A. (February 2009). "F/LOSS is Commercial Software". Technology Innovation Management Review. Retrieved 2013-08-08.
- Karl M. Popp (2011). Advances in software economics: A reader on business models and Partner Ecosystems in the software industry. Norderstedt, Germany: BOD. ISBN 978-3-8448-0405-8.
- "Commercial License for OEMs, ISVs and VARs". mysql.com. 2010-07-01. Retrieved 2013-08-10. "Q4: What is Oracle’s dual license model for MySQL software? A: Oracle makes its MySQL database server and MySQL Client Libraries available under both the GPL and a commercial license. As a result, developers who use or distribute open source applications under the GPL can use the GPL-licensed MySQL software, and OEMs, ISVs and VARs that do not want to combine or distribute the MySQL software with their own commercial software under a GPL license can purchase a commercial license."
- McMillan, Robert (2012-03-28). "Red Hat Becomes Open Source’s First $1 Billion Baby". wired.com. Retrieved 2013-08-12. "Other companies have made big money selling Linux — Intel, IBM, Dell, and others have used it as a way to sell hardware and support services — but Red Hat has managed the tricky business of building a software platform that big businesses will pay for."
- Mozilla Foundation Open Letter Orders Unofficial Mozilla Merchandise Sellers to Stop, Legal Action Hinted (March 16, 2004)
- The Wikimedia Shop, The official online store for Wikipedia and its sister projects.
- Molla, Rani (2013-08-06). "Hacktivist Richard Stallman takes on proprietary software, SaaS and open source". gigaom.com. Retrieved 2013-08-12. "He also claims software as a service (SaaS) is inherently bad because your information goes through a server beyond your control and that server can add additional software when it likes."
- Johnson, Bobbie (2008-09-29). "Cloud computing is a trap, warns GNU founder Richard Stallman". The Guardian. Retrieved 2013-08-10. "Web-based programs like Google's Gmail will force people to buy into locked, proprietary systems that will cost more and more over time, according to the free software campaigner"
- List of free-software licences on the FSF website: “We recommend that developers consider using the GNU AGPL for any software which will commonly be run over a network”.
- Tiemann, Michael (2007-06-07). "GNU Affero GPL version 3 and the "ASP loophole"". OSI. Retrieved 2013-08-19.
- Why did you decide to write the GNU Affero GPLv3 as a separate license? on gnu.org
- Byfield, Bruce (2005-09-21). "Google's Summer of Code concludes (first year)". linux.com. Retrieved 2013-08-08. "Google's Summer of Code (SOC), a program that matched computer science students with free and open source software (FOSS) projects and paid for results, is over."
- Sneddon, Joey-Elijah (2012-06-01). "Will You Help Change The Way Open-Source Apps are Funded?". OMGUbuntu. Retrieved 2013-08-08. "Lunduke is pledging to open-source and distribute his portfolio of hitherto paid software – which includes the Linux distro management simulator Linux Tycoon - for free, under the GPL, if he can reach a donation-driven funding goal of $4000/m. Reaching this goal, Lunduke says, ‘will provide proof for others, who would also like to move their software businesses to be open source, that it is doable.’"
- SourceForge.net Donation System on sourceforge.net
- "Mozilla Foundation Places Two-Page Advocacy Ad in the New York Times". December 15, 2004. Retrieved June 15, 2010.
- Marson, Ingrid (2004-12-16). "New York Times runs Firefox ad". cnet.com. Retrieved 2013-08-12. "Fans of the Mozilla Foundation's Firefox browser who funded an advertisement in The New York Times will finally get to see their names in print on Thursday."
- Leyden, John (2004-08-03), Mozilla to pay bounty on bugs, The Register, retrieved 2013-08-10
- Evers, Joris (July 25, 2005). "Offering a bounty for security bugs". CNET. CBS Interactive. Retrieved 12 August 2007.
- "Mozilla Foundation Announces Security Bug Bounty Program". Mozilla Foundation. Mountain View, California. August 2, 2004. Retrieved 2013-08-10.
- Lunduke, Bryan (2013-08-07). "Open source gets its own crowd-funding site, with bounties included - Bountysource is the crowd-funding site the open source community has been waiting for.". networkworld.com. Retrieved 2013-08-10. "Many open source projects (from phones to programming tools) have taken to crowd-funding sites (such as Kickstarter and indiegogo) in order to raise the cash needed for large-scale development. And, in some cases, this has worked out quite well."
- Arceri, Timothy (2013-07-26). "Help improve OpenGL support for the Linux Graphics Drivers". Indiegogo. Retrieved 2013-08-11. "Helping fund the time for me to become a Mesa contributor and document the experience to make it easier for others to understand where to start with the Mesa codebase. Many people have brought up the idea of crowd sourcing open source driver development. This is a small scale experiment to see if it could actually work."
- "Bountysource Raises $1.1 Million for the First Crowdfunding Platform for Open-Source Software Projects". finance.yahoo.com. 2013-07-16. Retrieved 2013-08-08.
- Callaham, John (2013-06-06). "Report: Google paying AdBlock Plus to not block Google's ads". neowin.com. Retrieved 2013-08-13. "Google is paying money to Eyeo, the company behind AdBlock Plus, so that its ads get through the browser ad remover."
- Hunt, Katherine (2007-05-24). "Sourceforge quarterly profit surges as revenue rises". marketwatch.com. Retrieved 2013-08-13. "Software Corp., late Thursday reported third-quarter net earnings of $6.49 million, or 9 cents a share, up from $997,000, or 2 cents a share, during the year-ago period. Pro forma earnings from continuing operations were $2.1 million, or 3 cents a share, compared with $1.2 million, or 2 cents a share, last year. The Fremont, Calif.-based maker of computer servers and storage systems said revenue for the three months ended April 30 rose to $10.3 million from $7.9 million. Analysts, on average, had forecast a per-share profit of 2 cents on revenue of $12 million."
- "SourceForge Reports Second Quarter Fiscal 2009 Financial Results".
- Hustvedt, Eskild (2009-02-08). "Our new way to meet the LGPL". Retrieved 2011-03-09.
- Mike Olson (co-founder and CEO of Sleepycat Software and Cloudera), lecture to Stanford University entrepreneurship students, 2013.11.13
- Twenty Years of Experience in Developing Software in Silicon Valley, Kim Polese lecture to Stanford University engineering entrepreneurship students, 2005.11.09
- "TTimo/doom3.gpl". GitHub. 2012-04-07. Retrieved 2013-08-10. "Doom 3 GPL source release [...] This source release does not contain any game data, the game data is still covered by the original EULA and must be obeyed as usual."
- STEEL STORM EPISODE 1 LIMITED USER SOFTWARE LICENSE AGREEMENT "Steel Storm Episode I EULA". steel-storm.com. Retrieved 2013-08-10. "For the purpose of this Agreement, the Art Assets include pk3 archive inside of "steelstorm/gamedata/" folder that contain two-dimensional and three-dimensional works of graphic art, photographs, prints and art reproductions, maps, charts, diagrams, models, and technical drawings, sound effects and musical arrangements, documentation and tutorial videos, and are licensed under Attribution-NonCommercial-ShareAlike 3.0 Unported license. The Engine, which includes Windows, Linux and Mac binaries, and the Engine's source code, are licensed under GNU GPL v2 license."
- Stallman, Richard (2012). "On-line education is using a flawed Creative Commons license". stallman.org. Retrieved 2013-08-10. "In my view, nonfree licenses that permit sharing are ok for works of art/entertainment, or that present some party's viewpoint (such as this article itself). Those works aren't meant for doing a practical job, so the argument about the users' control does not apply. Thus, I do not object if they are published with the CC-BY-NC-ND license, which allows only noncommercial redistribution of exact copies."
- "Eben Moglen, speaking about GPLv3 in Barcelona".
- Oram, Andy (2011-08-26). "How Free Software Contributed to the Success of Steve Jobs and Apple". radar.oreilly.com. Retrieved 2013-08-10. "the BSD license allowed Apple to keep its changes proprietary"
- NVIDIA Drops Their Open-Source Driver, Refers Users To VESA Driver on phoronix The xf86-video-nv driver has been around that provides very basic 2D acceleration and a crippled set of features besides that (no proper RandR 1.2/1.3, KMS, power management, etc.) while the code has also been obfuscated to try to protect their intellectual property.
- "Reasoning behind the "preferred form" language in the GPL". lwn.net. 2011-03-07. Retrieved 2013-08-19.
- Obfuscated “source code” is not real source code and does not count as source code. - http://www.gnu.org/philosophy/free-sw.html
- Phoronix - Towards A Real Business Model For Open-Source Software
- id Software releases Doom 3 source code on h-online.com (3 November 2011)
- id Software makes iPhone Wolfenstein open source by Spanner Spencer (March 2009)
- Shadow Warrior Source Code Released 3D Realms (1. April 2005)
- SOURCE CODE Selected games have had their source code released by us. These games are: Duke Nukem 3D, Shadow Warrior, Rise of the Triad, Word Whiz, Beyond the Titanic, Supernova, & Kroz. You can obtain these from our downloads page.
- Andersen, John (2011-01-27). "Where Games Go To Sleep: The Game Preservation Crisis, Part 1". Gamasutra. Retrieved 2013-01-10. "The existence of decaying technology, disorganization, and poor storage could in theory put a video game to sleep permanently -- never to be played again. Troubling admissions have surfaced over the years concerning video game preservation. When questions concerning re-releases of certain game titles are brought up during interviews with developers, for example, these developers would reveal issues of game production material being lost or destroyed. Certain game titles could not see a re-release due to various issues. One story began to circulate of source code being lost altogether for a well-known RPG, preventing its re-release on a new console."
- Bell, John (2009-10-01). "Opening the Source of Art". Technology Innovation Management Review. Retrieved 2013-08-09. "[...]that no further patches to the title would be forthcoming. The community was predictably upset. Instead of giving up on the game, users decided that if Activision wasn't going to fix the bugs, they would. They wanted to save the game by getting Activision to open the source so it could be kept alive beyond the point where Activision lost interest. With some help from members of the development team that were active on fan forums, they were eventually able to convince Activision to release Call to Power II's source code in October of 2003."
- "NETSCAPE ANNOUNCES PLANS TO MAKE NEXT-GENERATION COMMUNICATOR SOURCE CODE AVAILABLE FREE ON THE NET". Netscape Communications Corporation. 1998-01-22. Archived from the original on 2007-04-04. Retrieved 2013-08-08. "BOLD MOVE TO HARNESS CREATIVE POWER OF THOUSANDS OF INTERNET DEVELOPERS; COMPANY MAKES NETSCAPE NAVIGATOR AND COMMUNICATOR 4.0 IMMEDIATELY FREE FOR ALL USERS, SEEDING MARKET FOR ENTERPRISE AND NETCENTER BUSINESSES"
- "MOUNTAIN VIEW, Calif., April 1 /PRNewswire/ -- Netscape Communications and open source developers are celebrating the first anniversary, March 31, 1999, of the release of Netscape's browser source code to mozilla.org". Netscape Communications. 1999-03-31. Retrieved 2013-01-10. "[...]The organization that manages open source developers working on the next generation of Netscape's browser and communication software. This event marked a historical milestone for the Internet as Netscape became the first major commercial software company to open its source code, a trend that has since been followed by several other corporations. Since the code was first published on the Internet, thousands of individuals and organizations have downloaded it and made hundreds of contributions to the software. Mozilla.org is now celebrating this one-year anniversary with a party Thursday night in San Francisco."
- Proffitt, Brian (2000-10-13). "StarOffice Code Released in Largest Open Source Project". linuxtoday.com. Retrieved 2013-01-10. "Sun's joint effort with CollabNet kicked into high gear on the OpenOffice Web site at 5 a.m. PST this morning with the release of much of the source code for the upcoming 6.0 version of StarOffice. According to Sun, this release of 9 million lines of code under GPL is the beginning of the largest open source software project ever."
- Benkler, Yochai (April 2003). "Freedom in the Commons: Towards a Political Economy of Information". Duke Law Journal 52 (6).
- Dina ElBoghdady; Hayley Tsukayama (2011-09-30). "Facebook tracking prompts calls for FTC investigation". Washington Post. Retrieved 23 October 2011.
- Vaughan-Nichols, Steven. "No GPL Apps for Apple's App Store". Retrieved 23 October 2011.
- "Changing the VLC engine license to LGPL". Retrieved 23 October 2011.
- Netscape Navigator#The fall of Netscape