Internet self-retardation
The act of knowingly talking stupid while chatting on the internet. Usually in an attempt to sound cute or random.
Person 1: O HAI HOW ARE YEW?!

Person 2: do me know yew? I dun think yew know me.
 
Person 1: Oh I sowwy fo dat! i thought yew was summbuddy else!

Someone with intelligence: Stupid random morons. That's Internet self-retardation for ya.