its a derivitive of
apples i{insert capitalized noun here}
line. it is when somone uses sarcasm over the internet, usually with it so obvious that italics is unneeded.
most
people are able to figure it out without being told, though there are the select few who cant.
kate: damn internet
preston: yea, fuck it, i mean, what does it do for us anyways?
kate: communication
preston: someone doesnt get iSarcasm
kate: oh, who?