see whodat, also the name of a great hiphop site in the us of a (www.whudat.com) an the domain (www.whudat.de) of an crazy-ass german pimp named MC Winkel (he da shiznit!)
A nonsense substitute word used when you don't know the proper term for something or simply can't remember it. Derived from "Who'd have thunk it" and "what's this?".
Chicago Bears fan: "WTF did you say? Huh? Katrina should have swept you away... *starts cursing profusely and making more nasty Katrina remarks* "
Saints fan: "STFU - the Saints will demolish the Bears this year. The Saints will make your bears look like week koala bears smoking dope. As a proud member of the whodat nation I hereby bitch slap you - *POW* - WHODAT!"