alot of peeps i see in trade dont understand an acronym. then they keep calling them noob, nub, n00b....
to provent that from happening to u, here they are!

afk-away from keyboard
lfg-looking for group
wtb-wants to buy
wts-wants to sell
fg-forming group
lk- (rise of the) lich king
fta-for the alliance (acheivement)
woth-wrath of the horde(acheivment)
tb-tol barad/thunder bluff
sw-stormwind
df-darkmoon festival
dal-dalaran
dns-darnasus
uc-undercity
org-orgrimar
if-ironforge
sm-silvermoon
xdr-exodar
gl-good luck/gilneas

if your wondering any others, tell me in the comments. i will add the acronym.