Here are a few common acronyms used in e-mail that you may find useful and sometimes quite clever. Caution - make sure the person receiving your e-mail knows the acronym and won't think it's an insult.
BRB - Be right back
BTW - By the way
CUL - See you later
F2F - Face to Face
FWIW - For what its worth
FYA - For your amusement
FYI - For your information
GMTA - Great minds think alike
HHOK - Ha ha only kidding
IMHO - In my humble opinion
IOW - In other words
LOL - Laughing out loud
OIC - Oh I see
SO - Significant other
TIA - Thanks in advance
TNX or THX - Thanks
WB - Welcome back
WRT - With respect to
WTG - Way to go
