:-)
Happy
LOL
Laugh out loud

;-)
Happily winking
BTW
By the way

:-P
Sticking out tongue
ROTFL
Rolls on the floor laughing

:-(
Unhappy
BRB
Be right back

:~(
Crying
RTFM
Read the flaming manual

:-|
Unemotional
WTF
What the heck?

>:-(
Very unhappy
AFAIK
As far as I know

8-)
Wide eyed happiness
IMHO
In my humble opinion

:-O
Shouting
IOW
In other words

8-O
Wide eyed shouting
IMO
In my opinion

>8-O
Mad wide eyed shouting
FYI
For your information

|-|
Asleep
OTOH
On the other hand

==|:-)
Silly
TLA
Three letter acronym