I've been lurking for a long time, because I think some of these discussions are acutally interesting. So here's what I think (and most of it should be, and probably is, extremely obvious):
I think 0% of the members here actually believe the earth is flat. Some are here to test their debating skills (the dead giveaway is using words like "red herring", "straw man", etc...I mean, who really talks like that otherwise?). Some are here to actually discuss how anyone can prove the earth's roundness. Others might not know either way, and the point is that we really can't know without concrete proof. Bottom line, anyone who says they really believe is just messing with you for the sake of argument.
Does anyone believe in a flat earth? Probably not. Can anyone really prove either way? I don't know...but I guess that's the point of this place.
Again, it's all pretty obvious. But sometimes it can be interesting.