Unless it's unique, it'll probably die. But strictly for advertising advice: invite people you know. IM your friends, get them to IM their friends, and so on. You're not going to get much traffic simply by having a link that says "Please join my forum!" because everybody does that. Unless you get lucky and can get a bunch of people you know to join up, and your forum is just a "hang out" board, you'll probably need an actual website to draw attention--and that's a whole 'nother issue.