It is common to use acronyms on usenet and email. Here is what some of them mean:
AFAICR As Far As I Can Remember
AFAICS As Far As I Can See
AFAICT As Far As I Can Tell
AFAIK As Far As I Know
AIUI As I Understand It
ASL Age, Sex, Location?
B4 Before
BBL Be Back Later
BCNU Be seeing you
BRB Be Right Back
BSF But Seriously Folks
BST But Seriously Though
BTDT Been There Done That
BTW By the Way
CLM Career Limiting Move
CU See You
CUL See You Later
DWIM Do What I Mean
DWISNWID Do What I Say Not What I Do
F2F Face To Face
FAQ Frequently Asked Question
FOAF Friend Of A Friend
FOC Free Of Charge
FSVO For Some Values Of
FWIW For What It's Worth
FYA For Your Amusement
FYE For Your Entertainment
FYI For Your Information
<g> Grin
HAND Have A Nice Day
HTH Help That Helps
IAE In Any Event
IIRC If I Remember Correctly
IME In My Experience
IMHO In My Humble Opinion
IMO In My Opinion
IOW In Other Words
IRL In Real Life
ISTM It Seems to Me
ISTR I Seem to Remember
ITRO In The Region Of
ITRW In The Real World
ITWSBT I Think We Should Be Told
IYSWIM If You See What I Mean
JAM Just A Minute
KISS Keep It Simple, Stupid
L8R Later
LOL Laughs Out Loud
MFTL My Favourite Toy Language
MORF Male Or Female?
MOS Member Of Opposite Sex
MUD Multi User Dungeon
NALOPKT Not A Lot Of People Know That
NRN No Reply Necessary
OAO Over And Out
OBTW Oh, By The Way
OIC Oh, I See
OTOH On The Other Hand
OTT Over The Top
RFD Request For Discussion
ROTFL Rolls On The Floor Laughing
ROTFLMAO Rolls On The Floor Laughing My Arse Off
RL Real Life
RSN Real Soon Now
RT Real Time
RTFAQ Read The FAQ
RTBM Read The Bloody Manual
RTFM Read The Fucking Manual
RUOK Are You OK
SITD Still In The Dark
SO Significant Other
TIA Thanks In Advance
TIC Tongue In Cheek
TLA Three Letter Acronym
TNX Thanks
TPTB The Powers That Be
TTFN Ta Ta For Now
TTYL Talk To You Later
TVM Thanks Very Much
VC Virtual Community
WIBNI Would It Be Nice If
WRT With Respect To
YHBM You Have Bin Mail
YHM You Have Mail
YMMV Your Mileage May Vary