WordPress is open source software, licensed under the GPL (as its About page tells us). The question is: does the fact that WordPress is under the GPL mean that WordPress themes must also be under the GPL? This question of WordPress theme licensing has come to a head recently, as what Mitch Canter calls the great Thesis vs. WordPress theme debate.
Thesis is the flagship theme at DIYthemes. It is one of several WordPress themes developed by Chris Pearson. It is not under the GPL, because Chris doesn’t want it to be, and doesn’t think it has to be.
Why should a WordPress theme use the GPL? One way of making the argument is to use the following quote from the GPL FAQ. Combining two modules means connecting them together so that they form a single larger program. If either part is covered by the GPL, the whole combination must also be released under the GPL. A WordPress theme is a module that combines with WordPress core and with plugins to form a single larger program.
That’s the argument advance in a comment on the above-referenced great debate post. The comment is by Dougal Campbell, whose own post on the issue includes a good collection of links. Talking of links, my way in to this discussion was a post by Chris Cameron at RWW. That post focuses rather more on a specific exchange between Chris Pearson and Matt Mullenweg than on the wider issue.
I lean toward the view that WordPress themes (and plugins) are modules that combine with the core code. So they should be under the GPL, and hence free (as in freedom). If that makes a developer uneasy, well, maybe they should have thought of that before developing modules that combine with GPL’d code.
On the other hand, I think that reasonable people can disagree on this issue. So how to resolve it? Through the courts?
I have a few questions about the legal route. First, who has the best standing to bring suit? Would it be the WordPress Foundation (an organization of and from which I’ve heard little since its founding)?
Second, is this particular case too clouded by issues specific to Thesis to provide a good test of the basic question of theme licensing? (I’m thinking of statements that Thesis includes some code lifted from WordPress core.)
Finally, would a lawsuit be a good use of anyone’s resouces? I strongly suspect not.