i want to see how many we can come up with and see if you know the meaning. ill start it off and continue editing my post as we progress
IIRC
IMO
IMHO
IDB
STFU
IB
IMM
TTYL
GTG
GG
WTF
L337
OMG
...help me out, i want to see how big we can make the list

i bet you can name some of these:
AFAIK
AFK
AIM
ASAP
A/S/L
ATM
B B
BBS
BC
BCNU
BFN
BG
BICBW
BMG
BRB
BTA
BTW
CFN
CID
CUL or CUL8R
DYOH
DQMOT
EOM
FAQ
FWIW
FYI
GL
GMTA
GRA
GW
H HT
HTH
IAC
IAE
IDK
IIRC
IM
IMHO
IMO
IMPOV
IMS
IOW
JIC
JK
JTLYK
K
KIS
L8R
LOL
NBD
NP
NRN
OH
OIC
OTOH
OTP
P PLS
PLZ
POC
POV
ROTFL
RSN
RUOK?
SYS
TAFN
TBA
TBH
THX
TIA
TTFN
TTYL
WB
WFM
WTG
WU?
YT?
YW