"omphg" or 'omfg' Generally Means Om My fucking god.
People would Use this When something Stupid or irritating would Happen. Especially When 'n00b' Just keeps Egging you on.
<NooB> I r 5o 1337, joo h4v3 n0 id3a
<you>omphg(omfg) What a noob. Go get a life you incadescent Peice of Slaughter house mangled Ass wipe.
<NooB> stfuzors before i Haxxzors ur Nubatious Ass.
<you> lmao Only thing you can Hax Is a open source html Site, and get Access denied.
<someone-else> omphg BURN!