The following is a short list of both Emoticons and Acronyms commonly used on the Internet. There’s a lot more than this (some nice, some not) and if you’re interested in finding out more, do a search on Google for emoticons. [:)]
Or here’s another reference for more acronyms:
Internet Abbreviations for Penpals
Emoticons
Emoticons (emotional icons) are used to compensate for the inability to convey voice inflections, facial expressions, and bodily gestures in written communication. Some emoticons are better known as “smileys.” Emoticons can be very effective toward avoiding misinterpretation of the writer’s intents. While there are no standard definitions for the following emoticons, we have supplied their most usual meanings. Most emoticons will look like a face (eyes, nose, and mouth) when rotated 90 degree clockwise.
or Expresses happiness, sarcasm, or joke
or Expresses unhappiness
:] or :-] Expresses jovial happiness
:[ or :-[ Expresses despondent unhappiness
or Expresses jovial happiness
:I or :-I Expresses indifference
:-/ or :-\ Indicates undicided, confused, or skeptical. Also 
or :.
:Q or :-Q Expresses confusion
:S or :-S Expresses incoherence or loss of words
:@ or :-@ Expresses shock or screaming
or Indicates surprise, yelling or realization of an error (“uh oh!”)
Acronyms
AAMOF As A Matter Of Fact
AFAIK As Far As I Know
BBFN bye bye for now
BFN bye for now
BTW by the way
DITW Dead In The Water
DYOH Do Your Own Homework
EOL end of lecture
FAQ frequently asked question(s)
FITB fill in the blank
FUD Fear, Uncertainty, Doubt
FWIW for what it’s worth
FX Effects
FYI