[dwyer]

> most of the public content is under free licenses

Is it? I've read reports that all but a fraction of Github repos are single-commiter code dumps.

> the TOS explicitly dictates that you grant certain licenses to other users for free

Where?

https://help.github.com/articles/github-terms-of-service/

The only stipulation I see is:

> By setting your repositories to be viewed publicly, you agree to allow others to view and fork your repositories.

Unfortunately, the TOS doesn't provide a clear legal definition of fork. Does it go beyond clicking the fork button and copying the repo across Github servers? Does it including cloning the repo to a local disk? Or running the code? Or maintaining a derivative project?