AFAIK - As far as I know
AFK - Away From Keyboard
ASL? – Age ; Sex ; Location?
ATM - At The Moment
AYBABTU - All Your _base_ Are Belong To Us
BRB - Be Right Back
BTW - By The Way
CGI – Computer Generated Imagery
CIHYS? - Can I Have Your Stuff?
COT – Centre Of Attention
FB – Fringe Benefits
FBN – Fly By Nighter
FFS - For Fuck Sake
FWIW - For What It's Worth
FYI - For Your Information
GBOT - Get Back On Topic
IAFO – I Am Fucked Off
IAGTKY - I Am Going To Kill/Kiss You
ICBA - I Can't Be Arsed
IDC - I Don't Care
IDFC – I Don’t Fucking Care
IDCOB - I Don't Care One Bit.
IGMC - I'll Get My Coat.
IIRC - If I Recall (or Remember) Correctly
IMO - In My Opinion
IMHO - In my humble opinion
JPMSL - Just Pissed Myself Laughing
KISS - Keep It Simple, Stupid
LMAO - Laugh My Arse Off
LMFAO - Laugh My Fucking Arse Off
LMTO – Laugh My Tits Off
LOL - Laughs Out Loud
LOLZ - Expressing laughter
MSM - Main Stream Media
MYOB - Mind Your Own Business
MYOFB - Mind Your Own Fucking Business
NFW – No Fucking Way
NWO - New World Order
NPT - No Planes Theory
NSFW - Not Safe For Work
OFFS – Oh For Fuck Sake
OIC - Oh, I See
OMG - Oh My God
OMFG - Oh My Fucking God
OP - Opening Post or Original Poster
OTOH - On The Other Hand
PC – Political Correctness
PCGM – Political Correctness Gone Mad
PC – Personal Computer
PMSL - Pissed Myself Laughing
PITA - Pain In The Ass
POV Point Of View
ROFL - Rolls On Floor Laughing
ROFLMAO - Rolling On the Floor Laughing My Arse Off
RTFM - Read The Fucking Manual
SATLO - Something Along The Lines Of
(Sp?) - I am not sure of the spelling of that last word
STFU - Shut The Fuck Up
SUYP - Shut Up You Pervert
TUVM – Thank You Very Much
TBH – To Be Honest
TPTB - The Powers That Be
WIP - Work In Progress
WTF - What The Fuck?
WTG - Way To Go
WTC – World Trade Centre
WYSIWYG - What You See Is What You Get