I’ve been reading up on copyleft licenses. I’ve been tackling the question of whether the GNU FDL (GNU Free-Document License – the license for all content at Wikipedia) is compatible with more proprietary licenses? In other words will it be possible to straight-up copy all Wikipedia content and drop it into Google Knol?

You have to imagine that some young hacker is going to write a Perl script to take the content from every Wikipedia page, put it all in Google Knol, and then claim a piece of the AdSense revenue that Google shares with authors. This is inevitable. The bigger question is: is this legal?

The answer to this question depends on the license Google chooses for the content on Google Knol. I don’t think that’s publicly available yet (except to the invite-only beta testers), so perhaps it’s not possible to answer this question now. Is the GNU FDL compatible with Squidoo’s license? Or with HubPages’ license? Or Mahalo’s license?

UPDATE: The sample Google Knol page (linked from the Google blog post announcing the launch) invokes the CC Attribution 3.0 Unported License. This license is very liberal and does not explicitly block commercial reuse. However, because it’s a CC license, it’s not compatible with the GNU FDL currently. Wikipedia claims to be working on CC compatibility, but now that Google is endorsing CC licenses with Google Knol, I suspect that Wikipedia will be more reticent to adopt CC.

This is a fascinating update because it means that Google Knol content can legally be used in Wikipedia, Mahalo, etc… but the opposite is not true. That said, I’m sure we will see Wikipedia content all over Google Knol because no one respects copyrights anymore.