You’ve probably seen those Themes that include something in the order of:

• “By downloading and using this theme, you agree to link back to our site”

In this video, WordPress creator Matt Mullenweg talks about the WordPress GPL and how any works built on it need to follow the original license, meaning that Theme creators can’t rope you into including a link back to their site, like some do. Of course, if you want to link back to them to thank them for their work, that’s fine.

“If you do redistribute your derivative product in any way, you can’t take away freedoms from what you’re distributing. So for example, if I made a theme and I sold it to you that’s fine, but I can’t say you can only use this on one site or you have to leave my link in the footer or something like that. You should have the ability to modify it, just like you can modify WordPress.”
- Matt Mullenweg

For themes that conform to the original WordPress license, you can go to Studiopress. Matt mentions it at the end of the video.

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