Quote Originally Posted by Ebezaanec View Post
Some ones I can think of are:

Proc- Programmed Random OCcurence or PROCedure (someone may have to clarify this)
Alt- Alternate Character/Toon
AFK- Away From Keyboard
ATM- At The Moment
IGN- In Game Name
PM- Private Message

I'll think of more sometime later...
Proc is when a weapon, an armor etc. gives a special effect like for example fireballs around you or so at a random time.