AFK            Away From Keyboard 
ATM            At The Moment 
BBIAF          Be Back In A Few 
BBL            Be Back Later
BBS            Be Back Soon
BRB            Be Right Back 
BTDT           Been There Done That
BTDTMT         Been There Done That Many Times
BTW            By The Way 
C U L8R        S(C)ee Y(U)ou L8(ate)R 
C Ya           S(C)ee Y(Ya)ou 
EG             Evil Grin 
EMTA           Evil Minds Think Alike
GMTA           Great Minds Think Alike 
IMO            In My Opinion 
IMHO           In My Humble Opinion 
IRL            In Real Life 
JK (J/K)       Just Kidding 
LOL            Laughing Out Loud 
LTNS           Long Time No See 
NP             No Problem 
OIC            OH I S(C)ee 
re             REpeat Hi 
RL             Real Life 
ROFL/ROTFL     Rolling On (The) Floor Laughing 
TTFN           TaTa For Now 
UR             Your/You're
WB             Welcome Back