Although more a forum abbreviation than anime term, it's often used here:
Forum abbreviation for "FTW"
FTW = For The Win
Further reading for forum abbreviations:
IIRC = If I Recall Correctly or If I Remember Correctly
IMO = In My Opinion
BTW = By The Way
LOL = Laughing Out Loud
ROFL = Rolling On The Floor Laughing
FYI = For Your Information
FWIW = For What It's Worth
TRSI = The Right Stuf International
Also of note:
Items contained between two asterisks at the end of a sentence represent a physical act on the part of the writer (poster).
For example: OMG your post is sooo funny! *falls out of chair*
Translated: I laughed so hard at what you wrote that I fell out of my chair.
No matter where you go, there you are.