I would assume it's because my post count is low, but I will randomly get the message that my post will not be visible until a moderator has approved it. It doesn't happen every time either. For example, I posted 2 responses in a thread just fine, the third one said it required moderation, the 4th posted without incident. There was nothing but text in each post, and the one that wouldn't post wasn't even the longest one. Ideas?