ImFO
Also IMFO or imfo, could stand for either "I'm fucking original" (usually used in a sarcastic or mocking fashion) or "In My Fucking Opinion" (usually tacked on at the end of a sentence).  
Fag: Check out my Sonic recolor.  
Queer: Oh, ImFO.  

Nancy Pelosi: We need to work toward the goal of equalizing income in our country and at the same time limiting the amount the rich can invest.  
Thinking Man: We need to work toward shutting you fucking mouth, IMFO.  