I'm not a 'board guru' but I don't think smilies will help traffic at all.
I've seen plenty of large websites that seem popular content-wise but the forums are largely empty...people usually need a reason to initially sign up to a forum...like getting help for a game, or asking a question about how to promote forums. lol
Does the rest of your site allow comments to articles/content? If so, that might deter people from forums themselves. If not, I've seen some websites put a link at the bottom of an article that says something like "Discuss (this topic) in our Forums." Maybe that would help get the ball rolling sometimes, or at least make it more likely people would click over to the forums instead of just ignoring a generic "Forums" menu link? I think I need to start doing that on my own site.
Another thing I've noticed is that by and large, users tend to be fiercely loyal to any forums that they already reguarly frequent...not much incentive for them to move to another if they're happy where they are...thus, putting links to your own forum in another forum typically gets you curioisty hits, but not much registration/activity. And of course, an empty forum is not attractive even if people see 'potential' - makes that forum-member pay-service almost sensible, haha.