If you’re at all involved in the WordPress community, whether you’re an established or aspiring theme or plugin developer, or contributor, or bug squasher, then you would be aware that there has been a long-standing conflict between WordPress’ founder, Matt Mullenweg, and a number of premium theme developers who refuse to abide by extensions of the GPL towards themes.
Matt suggests (I think accurately) that a theme that is provided for WordPress (it does not work without WordPress) is a derivative work and requires GPL compatibility. He also suggests (accurately, I think) that GPL compliance would only enhance DIYTheme’s business as evidenced by countless other proprietary software providers who have gone open source.
I agree with Aaron’s parenthetical opinions, but have to add that the GPL’s extension is towards the PHP code only and that images and CSS that comprise front-end may be licensed under another license. I also have to add that the GPL is extended to themes that are released “for distribution,” which protects my work when I develop a custom theme for someone.
Of the very few non-GPL-licensed theme developers, the most notorious is Chris Pearson, developer of the Thesis theme. I missed the interview mentioned by Aaron, given that it happened during office hours and I was at work, but I saw tweets, and it seemed the conversation ended on a very open-ended, but acrimonious manner. Chris Coyier has a (mildly humorous) summary. It looks like we’ll be seeing a court case soon enough.
My opinion on this matter, just as about almost everyone’s opinions on this, does not matter. What matters is that WordPress is a community project, and that the rules of game theory apply. Isolation in this project is worse than death.
I’ve been a critic of the WordPress project’s leadership, but never personally, and always on matters which I considered material and I’ve always tried to suggest, no matter how mean I’ve become, a course of action. A lot of Matt’s critics, however, are nihilistic and have nothing to offer. They don’t even have an endgame. They just revel in the power and authority that notoriety affords.
I have made my peace about the GPL-ness of WordPress themes. The safeguards to protect my intellectual property with regards to design already exist. I really don’t have much else to add, except that I personally would rather get back to work and leave this conflict to the courts.