BUFF - Positive status effects casted on you by you OR by someone else. Usually on for a duration or just turned on. These effects can make you do more damage, regenerate health or regenerate power. Depends on what class you or the other persons are.
DEBUFF - Negative status effects casted on you OR on your enemy. Usually on for a duration. These effects can make you/enemies do less damage, have less health as a %. Depends on what class you or the other enemies are.
DOT - damage over time
AOE - area of effect. example: an explosion doing splash damage. it can pertain to buffs aoe or debuffs aoe too.
REGEN - regeneration of mana or health.
HOT - heal over time.
TANK - a hero who's main role is to take damage for the team. The wall, the first line and main line of defense.
LVL - what character level you are.
AGRO - aggression. threat level, the ememies attention to a team mate.
ADD - a respawned or wandering enemy who jumps into a fight unexpectedly. "Oi, we got 5 adds behind us!"
INSTANCE - a generated place for the group to privately explore. usually indoor by apearance. alerts, raids, duos(?), Arenas are all instances.
LFG - Looking for group
LFM - Looking for More
LF - Looking For...
WTB - Want to Buy
ATM - At the Moment
RL - Real life
BRB - be right back
some common ones from past MMOs. --- Paintings, Drawings, Charcoal work, etc. - http://www.flickr.com/photos/edwardart/ Winners don't eat meat. - William S. Broccoli