I wish FB would report when an account was established. I could ask for access to the user's postings and try to get dates on those, but that seems too intrusive. I would just like to be able to say, "Thanks for trying to sign up, but you've only had this account for 15 minutes and I don't trust you. Come back in a year when you look less like a troll."

That's hardly a perfect filter, of course, but I think there's a use case for communities that err on the side of stability over the broadest audience.