More than you think you know. :-)
There are about, say, 40 to 60 or so posters that I know for sure aren't trolls. I put stock in what they say. And there's almost as many posters that I know for sure ARE trolls. I like to needle them occasionally just to let them know they've been noticed. The rest of FR I take with a grain of salt.
Hehe I know that needled feeling. When I first came around back in September every time I posted something that was a bit against the grain I would get some very inquisitive replies. When you hang in there and discuss your positions you prove yourself. The Trolls and impersonators tend to post and run.