I saw an intriguing post the other day by Jennifer Schiffer on WordPress, themes and the GPL. She linked to a video of Matt Mullenweg (one of WordPress’ lead developers) who was talking about why WordPress was a GPL product (short answer: they didn’t really have a choice because WP is based on b2, which was GPL) and, more specifically, was talking about why themes and plugins are also then GPL.
The truth of the matter is that the GPLv3 is a very restrictive license, in as much as it’s also a harbinger of freedom. The GPL was written in a way to specifically retain the freedoms it grants through successive iterations of a particular product, or its add-ons. This means that if you like a GPL product, develop a derivative work, a modification, a plug-in or any other type of add-on, the resulting work is also going to be covered by the GPL (you do not have a choice in this).
“You may not impose any further restrictions on the exercise of the rights granted or affirmed under this License.” – Section 10 of the GPL
This means that unless the WordPress GPL (yes, they’re specific by product… you can ADD restrictions if you want… so no 2 GPL’d products are necessarily identically licensed – we’ll talk about this in a minute) allowed for a theme developer to restrict the distribution of a theme, a theme developer isn’t allowed to add that restriction on their own. Your development on a GPL product inherits the license of the original product.
Inheritance is a powerful concept because it creates license congruity, ad infinitum, for all downstream works of the original code. It would be extremely difficult to manage license compliance if WordPress had one license, but a plug-in had a different one.
But there’s apparently a wonderful new theme available for WordPress called Thesis. Its developer sells two several different versions of the theme (selling under the GPL is fine). The problem comes to light when you look at the options:
- Personal: one site only; footer link must remain intact; can’t re-sell theme or modifications
- Developer: can create multiple sites and must pay Thesis developer for each site deployed; can remove footer link; can’t re-sell theme or modifications
And these options are problematic because they violate the GPL v2 under which WordPress is licensed. Specifically, Section 2, which states, in part:
“You must cause any work that you distribute or publish, that in whole or in part contains or is derived from the Program or any part thereof, to be licensed as a whole at no charge to all third parties under the terms of this License.”
and Section 6:
“Each time you redistribute the Program (or any work based on the Program), the recipient automatically receives a license from the original licensor to copy, distribute or modify the Program subject to these terms and conditions. You may not impose any further restrictions on the recipients’ exercise of the rights granted herein. You are not responsible for enforcing compliance by third parties to this License.”
(Note that v2 and v3 of the GPL are vastly different animals… and v2 was actually more in the realm of “free as in free beer” than v3, which touts freedom as “free as in free speech, not free beer”.)
So, in fact, the Thesis theme, as a WordPress derivative work, is bound to the GPLv2 license that WordPress is licensed under. As such, even the sale of the theme is a problem, as are the one-site-only restrictions and the “can’t re-sell” restrictions. Note: the footer link restriction is probably fine, as it could qualify as the attribution allowed under the GPL. Additionally, it could be argued that the fee charged is for the “physical act of transferring a copy” as allowed by Section 1 of GPLv2, but even then, the remainder of the unauthorized restrictions are still problematic.
But who is going to do anything about this violation? Who has the right to enforce the license? WordPress? The folks at b2 (WordPress’ predecessor)? Any particular end user? Technically, it’s the folks at WordPress who have the right to enforce their license upon theme and plug-in developers. They have the ability to potentially even sue to prevent a rogue developer from violating their license with WordPress [though I’m guessing that a theme developer is going to try to argue that a theme isn’t a derivative work or a modification]. But this is inherently difficult. So instead, WordPress is taking a slightly different tack. They’re going to create a Theme Page on the main WordPress website which only lists themes that follow the GPL (by the way, all derivatives have to be GPLv2 licensed, as the WordPress license doesn’t allow for newer versions of the GPL to apply). I’m guessing that Thesis won’t be listed.