Implications of the GPL for WordPress themes and plugins

In Uncategorized on 2009-07-03 by Kyle Maxwell

Automattic, the company behind WordPress (the software running this and millions of other blogs and web sites) confirms that they believe that WordPress themes and plugins constitute derivative works of their software. This should be fairly clear, as the code for these themes and plugins essentially becomes a part of the running installation. In the case of WordPress, the software license expressly permits this sort of growth and modification because they’ve licensed it using the GNU General Public License — the same license behind Linux.

Since a lot of the folks that use WordPress and other forms of social media might not have a great deal of familiarity with the GPL and the legal implications of Open Source and Free Software in general, let’s review some of the key points that relate to this whole issue: the Free Software Foundation created the GPL in a desire to ensure freedom for users. When you license your software under the GPL, you basically make a contract with your users that allows them to use it for whatever they want as well as to modify and re-distribute it to their hearts’ content. But this freedom comes with a price: all derivative works must also be GPL. If you’ve ever heard about the “viral nature” of the GPL, this means that you can’t use GPL code in your project unless you license it under the GPL also (or a compatible license).

Despite what some folks have tried to charge, the GPL is not a “communist” license, and using GPL software in your organization does not mean that all software you produce must carry that license. In fact, the GPL encourages entrepreneurship and innovation by making sure that as many people as possible can use and improve the software. You can still make money with GPL software, by the way. While you can charge for distribution, remember that recipients can choose to re-distribute it. So while the makers of the Thesis theme can still sell it, those who purchase it can re-distribute the code in it freely according to the terms of the GPL. (The GPL does not cover the graphics & CSS in themes and plugins, which can have their own copyright protection or include trademarks, so take care.) But more importantly, and despite what others might think, the GPL fosters activity by helping create an entire ecosystem around the software. You can sell other services like support, customization, additional data feeds, and more. For example, if you write a better anti-spam plugin, you can charge for access to your blacklist or for technical support.

Personally, I welcome this clarification. Not only does it mean that I have a wider range of software to choose from for my own site, it also means that as I start to develop for the WordPress platform, I can learn from what my predecessors have done and help others do the same.

Key points here:

  • Your blog doesn’t fall under any sort of GPL requirements.
  • You can redistribute the PHP code in themes and plugins, but verify before doing that with the graphics and stylesheets.
  • Companies can still make money off themes, plugins, and WordPress in general, but they can’t do it by taking away the freedom of the software.

I am not at attorney and this is not legal advice. If you believe you have violated the GPL or have specific questions about your situation, you should discuss these with your own attorney.


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