It seems silly to the point of hubris, but I've created a mailing list for users of my twitteR R package.
While I'm not exactly inundated by emails from users, I do find that two things tend to be true. The first is that the same questions are often repeated (ok, I could have just made a FAQ!), but the other is that these topics tend to come in clusters where I might be asked the same question several times over the course of a few days. It seems to me that the mailing list can provide searchable archives and an efficiency of action when answering those questions.
I also tend to be asked questions regarding practical applications of this package. The real experts in these matters are other users, so my hope is that the mailing list might help facilitate those sorts of discussions.
To sign up for the mailing list, simply go to the Mailman page and register there. Archives are open to the public although posting is limited to members (I think, I should double check that setting).