Contrary to popular belief, QQ is not a set of crying eyes. It actually originated with the advent of Warcraft II. On battlenet, you could press ALT+Q+Q to immediately exit the match and program. Thus the term "QQ" was to tell people to just quit because they are unskilled. The term later developed and lost it's origin and is usually mistaken as crying eyes.
In contemporary gamer culture, QQ has become the mainstream emoticon for crying eyes, though it is still often used in it's traditional sense.
Per usual, the mage boards were flowing with tears when an intelligent, witty, philisophical player directed at the whiners (see Faxmonkey, beta comments) --> less qq more pew pew.
Originally started in Warcraft, where Alt+QQ is a hotkey to quiting the game.
When someone bitches or whines everyone would say 'QQ', telling them to quit the game because they suck so much.
It often confuses people into thinking that it means, "Cry more noob", but this is totally incorrect. The fact that 'QQ' looks like a pair of teary eyes is just a mere coincidence.
A term used normally for players with "ranged" attacks in a video game, used when someone is crying (hence the Q.Q face looking like the O.O face with tears) and not doing anything. The phrase "pew pew" is an onomatopoeia for a gun firing.
A "QQ thread" in the discussion forums of MMORPGs like World of Warcraft, is where a user starts a discussion thread which is basically a complaint, whine or whinge about something in the game they are not happy with.
QQ itself is meant to symbolise someone crying; the Qs looking like eyes with tears streaming from them.
"This isn't a QQ thread, but please nerf class X as they beat me in combat and thus must be overpowered and imbalanced!"