While the Oxford English Dictionary has strict rules about who gets to go to its old and esteemed club, its cousin the Oxford Dictionaries Online is a lot looser. That’s why in June it was a big deal that the OED added “tweet”; typically, a word has to be around for ten years to prove itself worthy of admission. But the ODO lets basically anyone in – which is why “twerk,” “selfie” and “girl crush” are partying it UP right now in the English language’s hottest club.