BRB – be right back
BIO – going for bio break (washroom break)
AFK – away from keyboard (I am gone for a few minutes)
BTW – by the way
KK – OK (commonly used by online gamers to acknowledge that a message has been received)
TTYL – talk to you later
BFN – bye for now
TTFN – ta-ta for now
BFF – best friends, forever
DH – darling husband
CYA – see ya (or it could also be: cover your a*s)
CUL8R – see you later
IBTL – in before the lock (for when you post a message prior to the administrator locking the heated discussion thread)
IMHO – in my humble opinion
IMNSHO – in my not so humble opinion
FMV – fair market value (for selling items online)
LOL – laughing out loud
MT – mistell (commonly used by online gamers to say that they made a mistake and mistyped their last message)
NWT – new with tags (for selling items online)
NWOT – new without tags (for selling items online)
OOAK – one of a kind (for selling items online)
PMSL - P*ssing myself laughing (a common UK expression)
QFT – quoted for truth (a compliment to another person on the forum)
ROFL – rolling on floor laughing
ROFLMAO – rolling on floor laughing my a*s off
RTM – read the manual
RTFM – read the f***ing manual (to show frustration at someone's ignorance of basic knowledge)
GG – good game
THX - thanks
TX - thanks
TY - thank you
NP - no problem/you're welcome
PLZ - please
W/E - whatever
ASL – age / sex / location?
RL – real life
IRL – in real life