How do you know all those tweet-happy celebrities are the real deal? 50 Cent, Keith Olbermann, Christopher Walken, and Britney Spears are just a few of those with questionable Twitter identities.

It takes just one crack about Britney Spears's vagina's "razor-sharp teeth" on her official Twitter feed — a juvenile stunt by a hacker — and her entire social media operation is thrown into disarray.