Here's a list of abbreviations and acronyms commonly used in internet chatting. There are many such lists online already, but they all try to be as long as possible and therefore include things that noone ever uses, which just makes them unpractical. In this list I only include abbreviations that I see being used regularly. Many of them relate to gaming and the trashtalk that goes with it :)

English

• *action* = something between ** represents an action; e.g. *looks puzzled*, *coughs*
• 1337 = l33t = elite
• afaik = as far as I know
• afk = away from keyboard
• asap = as soon as possible
• atm = at the moment
• bf = boyfriend
• brb = be right back
• btw = by the way
• cba = can't be arsed
• cu (l8r) = see you (later)
• dl = download
• ffs = for fuck's sake
• fu = fuck you
• FYI = for your information
• gf = girlfriend
• gg = good game
• gl = good luck
• gn = good night
• gtg = got to go
• hf = have fun
• hth = hope this helps
• ianal = I am not a lawyer
• ic = I see
• iirc = if I recall correctly
• imo / imho = in my (humble) opinion
• ip = internet address in numbers (internet protocol), e.g. 125.168.33.68
• irl = in real life
• l33t = elite
• j/k = just kidding
• k = okay
• lol = laugh out loud (just used like 'haha')
• m8 = mate
• mom = wait a moment
• n1 = nice one
• nm = never mind
• np = no problem
• NSFW = not suited for work
• omg = oh my god
• otoh = on the other hand
• pls = please
• pp / ppd = postpone / postponed
• ppl = people
• pwnd = owned
• rgr = roger (understood / okay)
• rofl = rolling on the floor laughing (just used like 'haha')
• stfu = shut the fuck up
• ta = thanks
• tbh = to be honest
• thx = thanx
• ty = thank you
• url = web site address (uniform resource locator)
• wb = welcome back
• wtf = what the fuck

Flemish

• ff = effe (quickly, a moment)
• gvd = godverdomme (goddamn)
• idd = inderdaad (indeed)
• iig = in ieder geval
• lmd = lijkt me duidelijk (seems obvious to me)
• mss = misschien (maybe)
• n8 = nacht (good night)
• w8 = wacht (wait)