afk: away from keyboard
u: you
ur: your
cu: See you
cya: See ya (same as see you)
brb: Be right back
gtg: got to go
ruok: Are you OK?
oic: Oh, I see
bs: bullshxt
wth: what the hell
wtf: what the fcuk
j/k: Just kidding
lol: Laugh out loud
omg: Oh my god
tks/ thx/ thz: thanks
sry: Sorry
nvm: Never Mind
dunno: don't know
fyi: For Your Information
asap: As soon as possible
btw: By the way/between
imo: In my opinion
sth: something
sb: somebody
on9: online / 戇 "dog"
be4: before
5d: 快o的
886: bye bye law
3q: thank you
XD: 大笑
Orz:
http://www.diudiu.com.cn/jacky/upload/h2orz.jpg
me2: me too