When you accidentally post unintelligible status updates on social networks by involuntarily pressing buttons on your PDA or cell phone.
"WTF was that nonsense on Facebook man?"
"Damn...musta been another butt-post...I gotta stop carrying that Blackberry in my pocket!"
The posting of gibberish to Facebook or in an e-mail because your phone is in your pocket and you somehow clicked POST or SEND.
A typical butt post looks like this: "NNNBJJJGHHHTUUYJJHMMBJJGUUTKMMBMMBLLKMNNVHHFGJJGNMB"
Karen checked in at an airport then butt posted fifteen lines of random characters to her status update.