I've been spending a lot of time today wondering why Matt cares so much about what license Chris uses - it seems like no real harm is being done to either party here, but both parties are digging in their heels so strongly I find it hard to believe it's purely a philosophical difference.<p>I just had a thought, and I'd like to sanity check it. I don't know Matt or Chris, but I use both Wordpress and Thesis every day, so consider this 100% speculation based on my experience:<p>1. I use Thesis to manage almost all of my Wordpress sites because it makes my work significantly easier - Thesis extends WP in many useful ways that aren't built into WP core. I'm capable of doing it all myself in the code, but it's much easier to handle it in Thesis, which I think is a major reason why it's so popular.<p>2. If Thesis adopted the GPL, that means the code is open to be distributed and reapplied by anyone for free. That means Thesis features could legally be added to WP Core <i>without paying Chris royalties</i>. In Matt's eyes, that would be great - it would make WP better by incorporating many new features that users have demonstrated they like/want/need. (I'm pretty sure some former WP plugins have been added to core over time in this way.)<p>3. If Thesis' features are incorporated into WP Core, Chris' very profitable business evaporates almost immediately - the value is in the added functionality, not the stylesheet, so there'd be no reason for anyone to purchase Thesis. That means if Thesis is forced to adopt the GPL, Pearson stands to lose <i>big time</i>.<p>4. If Thesis' commercial license is legal (which the post at <a href="http://perpetualbeta.com/release/2009/12/why-the-gplderivative-work-debate-doesnt-matter-for-wordpress-themes/" rel="nofollow">http://perpetualbeta.com/release/2009/12/why-the-gplderivati...</a> makes a strong case for, depending on the definition of "derivative work" when it comes to software), any IP from Thesis incorporated into WP Core without permission or royalties would violate Chris' rights and potentially generate a valid IP infringement lawsuit.<p>5. Based on the tone of the conversation so far, I don't think Chris would ever give Matt (or anyone else) permission to use IP from Thesis in WP Core without a massive royalty payment.<p>6. If Matt wants to have the freedom to incorporate Thesis features into WP Core, but doesn't want to pay Chris royalties, he'd have a vested interest in publicly pressuring Chris into adopting the GPL, which is what Matt appears to be doing. Chris finds that offensive, so he's telling Matt to fuck off and sue him if he really wants to push the issue. To Chris, a lawsuit (which will be easier to defend because his business partner, Brian Clark, is an attorney) is a small price to pay to prevent losing millions in revenue, and he believes Matt will lose in the end.<p>Again, total speculation, but this is the only reason I can think of right now they'd go after each other so strongly. Thoughts?