I agree, specially for someone who's unsure at the very start of their sexuality, just getting on here and reading the post is a big step. There's no real good answer for that question But I do think that from the moment you register it makes more sense to start posting.
For me, I first register because I wanted to give my comment on CJ's story FtL. For a while I only posted when new addition was up. That's also because, I see it a little as a privilege to be member here, so I was new and didn't know what to post, and was dam scared of pushing the limits. But eventually because I've gotten more comfy, and also because I'm good enough at giving advise to people, I've started post.
Even now, believe it or not, I'm still scared to say wrong things, post and ask question that have been talked about at more than one occasion, piss off someone or worse be banned or something. Therefore, most of the time, I make sure that I post answer of more than a few words and restrain myself when what I want to write is for the benefit of only one. If that is the case for me, I'm sure there are many more like me who's just too scared to post.
I agree that post with just smiley in it is going overboard. Tho, I certainly won't complain about those who "think they need to add a reply to every post" because sometimes even if it's not obvious, it does get the discussion going or send the discussion in another perspective just as relevant. Beside, it's with the contribution of those that makes this forum the way it is and IMHO that's what create the great friendship on the interaction we have here.