In Japan, it's almost like "lol" or "haha". It comes from the term "笑う", or "warau", and it means "to laugh". The more w's, the more ha's, so to speak.
(12:23:30 PM) //change: it constantly gets my cpu load to 100%
(12:23:45 PM) AbsintheSyringe: i ja njoj kazem sto ti mene?
(12:24:17 PM) //change: wtf????
(12:24:25 PM) AbsintheSyringe: ww
In Starcraft 2 I often seen some people mistaken ww with gg. Koreans especially. "Well Won" seems the most suitable use of ww when used in gaming, other than gg "good game.