How are you planning on providing a means for people to distribute materials under a GPL-type licence?
That’s a much more complex issue. Certainly, I don’t see anything in the GeoCities FAQ’s or guidelines prohibiting an exchange of ideas. Quite the opposite, in fact. On the other hand, I’m not 100% sure that I want to distribute any actual material myself. Actual “Free Software” projects do very nicely with people volunteering to maintain certain sections and making those sections available themselves. I think that, if I keep the site here, I’ll end up more providing documentation, HOW-TO’s and guidelines on how to do this, at least on these pages, and keeping my contributions on pages elsewhere. That way, there can be no implication that I “own” this concept and there is no unintentional bias, either to me or anyone else.