The odds aren't as astronomical as you'd think, but they're not from the same world. Some aren't here. There's at least one person that is from a work of fiction. Buffy the vampire slayer, actually. Their lives have enough similarities that they are essentially the same person, but enough differences to suggest alternate realities. I know it sounds insane, but there are a lot of insane things here.
It definitely feels that way sometimes. I haven't exactly figured out how to stay off the radar yet. I try not to upset them when they make posts, though. It seems like everyone gets their turn no matter what, though.