Acronym for "I'm On A Boat."
Most commonly used as a text/email/IM/social networking sign-off to express extreme satisfaction with one's self.
Can be proceeded by or in conjunction with "Mother f^*k*r." (i.e., IOABMF).
Often used in drunk texts:
Person 1 (let's call her amy): Where the hell are you? I'm at the bar. Are you still here?
Person 2 (let's call him chris): IOAB. More specifically IOABMF.