"Your Fucking Caps Lock is On" Used to online bitchslap people, generally of an IQ approaching room temperature, who type shite in all caps because they think it makes their argument more persuasive to do the equivalent of shouting online.
'Tard: "OMG OMG UR RONG AND RITARDED STFU OMG OMG"
Response: "I offer a rare and not commonly known service.
It's called YFCLO. I surf the internet to warn people when YOUR FUCKING CAPS LOCK IS ON.
Oh, and STFU."