Being exclusively on Fakebook, IMO, is discriminatory against those who don't like it. Yet some people prefer it to e-group lists.
A dedicated forum is where it's at. Someone has to pay for hosting and upkeep, but the moment the owner no longer cares and the hosting bills don't get paid, the party's over.
Folks may not want to be on Facebook, but you don't have to use it for anything other than looking for the one or two groups you'd like to be a part of. All it asks for is an email and you can make up whatever name you want, and choose how invisible you'd like to be.
Of course, it also does some truly obnoxious features like suggesting useless groups, and nagging you to follow people who just seek more followers. Come to think of it, I think I'm not making a terribly good case for FB...
Come to think of it, hearing that Yahoo Groups will just become an e-mail group sounds like a technological step backwards.