Same thing as woot. A sign of excitement especially when playing shooting games when you get a kill or something really unexpected. When you get a double kill after saying lolcats! you might say double lolcats! then triple lolcats and so forth.

An image macro of a member of the feline species, usually superimposed with phrases that make little to no grammatical sense whatsoever; some of the phrases are echoic of Black Slang, 1337 speak, or gamerchatter.

fucking stupid..

cats made out of daily lol's said daily

laugh out loud, with cat on the end of it

An added extra to the normal use of 'lol'
usually used when something is funnier than a lol, (a more exaggerated lol).

When a cat of any breed, makes an action of making someone laugh. The word is usually said fairly fast.