224 --- "today, tomorrow, forever"
2B - "to be"
2B||!2B -- "to be or not to be"; from the C Programming Language logic operation 'OR'("||") and 'NOT'("!").

2TM --- "to the max"

AFAICR/S/T: As Far As I Can Recall/Remember/See/Tell
AFAIK: As Far As I Know
AFK: Away From Keyboard
AIGHT: short for alright, or okay
AIUI: As I Understand It
ASL: Age / Sex / Location
ASAP: As Soon As Possible
ATB: All The Best
ATM: At The Moment

B2B: 'Business 2 Business'
B4: before
B4N: bye for now
BBL: Be Back Later
BBS: Be Back Soon
BCNU: Be seein you
Bisi: Busy (Luxembourgish)
Blog: Weblog
BOFH: Bastard Operator From Hell
BOHICA: Bend Over, Here It Comes Again
BS: stands for bullshit
BSOD: Blue Screen of Death
BR: Best Regards (for emails)
BRB: Be Right Back
BRT: Be Right there
BTDT: Been There Done That
BTW: By The Way
BW: bandwidth

Crawl: Search or scan on the net.
CU or CYA: See you
CID: consider it done
Cyberspace: virtual reality, the Internet, the World Wide Web, and other kinds of computer systems or networks
CYA:Cover Your Ass
CSL:can't stop laughing
Cyber: through the PC or the net
CWOT:complete waste of time
C&V:chapter & verse (used in newsgroups)

DC'd: disconnected
DGT: don't go there
DL, d/l: download receiving data from a remote host
DMY: don't mess yourself
DON: Denial-of-Normal Originally used on Slashdot
DoS: Denial-of-Service
dun: don't
dunno:(I) don't know

F2F: Face To Face
FFA: Free For All
FFS: For Fuck's Sake
Flamer: one who writes incendiary
FOD (or FOAD): Fuck Off And Die
FOAF: Friend of A Friend
FPS: Frames Per Second
FTW: Fuck the World
FUBAR: Fucked Up Beyond All Recognition/Repair (from military slang; pronounced "foo-bar")
FUD: "fear, uncertainty, and doubt" (the purposeful spread of misinformation)
FWIW: For What It's Worth
FYI: For Your Information

GG:Good Game. Used to complement an adversary or ally.
GMTA:Great Minds Think Alike
GTFO: Get The Fuck Out
GTG: Got To Go (AKA: G2G)[4] and Good To Go

HAND: Have a Nice Day
Handle: name used in online chat, (AKA nickname), alias, screen/user name)
Hit: a request made to the Web server, (noun) the results of an internet search, (verb) loading a Web page.
Home: the website's main page,
Hot List: a good collection of files or urls
HTH: Hope This/That Helps, Happy To Help
Haxxor: (in games) Slang term used to describe one who uses modified (sometimes "hacked") content to beat other players. Also h4x0r in Leet.

IDK: I don't know
IIRC: If I Recall/Remember Correctly
IM : Instant Messaging using a software or cellphone hardware/software
IANAL: I Am Not A Lawyer
IMO: In My Opinion, IMHO: In My Humble Opinion
IMNSHO: In My Not So Humble Opinion
IOW: In Other Words
IRC: Internet Relay Chat
IRL: In Real Life
IYKWIM: If You Know What I Mean

Jaggy: aliased computer graphics
JK or j/k: Just kidding
JJ Just Joking
JOOC: Just Out Of Curiosity

Lag: Slow Internet speeds or high Internet latency; Lag is sometimes due to a server problem, but more frequently due to the connection between client and server.
Lamer: a know-nothing. One who is lame.
Lamerico: A website which is poorly designed, or its purpose is to cheat out users.
LOL: laughing out loud, laugh out loud, lots of laughter
LMAO: laughing my ass off, a variation of the above, with many variations and additional letters in the acronym
Lurker: one who frequents a message board without participating in discussions

m8: Mate
MOTD: Message Of The Day
MUD: "Multi-User Dungeon"
MUSH: "Multi-User Shared Habitat"
MWISOMDNA: "Max Weinberg Is Standing On My Doorstep Naked Again" from Late Night with Conan O'Brien
MYOB : Mind Your Own Business

Newbie: an inexperienced user of a system, formal for novice
newb: (see above newbie)
noob:(see above newbie)
n00b:(see above newbie)
NIFOC: Naked in Front of Computer
NM or n/m: No Message or No More, is also a slang for Not Much.
NVM: Nevermind
NP: No Problem

OIC: Oh, I See
Op or Sysop: Operator / Moderator (system operator)
OS: "Operating System"
ORLY: Oh really?
OT: Off Topic
OTOH: On The Other Hand
OMG, OMFG: Oh My God/Gosh, Oh My Fucking God

P2P: peer-to-peer, person to person, player to player
PEBKAC/PEBCAK: Problem Exists Between Keyboard And Chair
Ping: Are you there?
PITA: Pain In The Ass
PLMK: Please Let Me Know
PM : Personal Message
PWN/PWNED: "own or owned," a slang often used to express superiority over others

Rehi: hello again (resay hi)
RL: Real Life
RO(T)FL: Rolling On (The) Floor Laughing
ROFLMAO: Rolling On Floor Laughing My Ass Off
RSN: Real Soon Now (used sarcastically)
RTFM: Read The Fucking Manual

SCNR: Sorry, Could Not Resist
Smiley: emoticon
SNAFU: situation normal, all fucked up
Snail Mail: normal paper mail service
Spider: the program behind a search engine
Spam: junk email, message or may also refer to a senseless post in a forum
specs
STFU: Shut The Fuck Up

TBH: to be honest[
TH(N)X: Thanks
TIA: thanks in advance
TINC: there is no cabal (a term discouraging conspiracy theories)
TLDR: Too Long Didnt Read
TOS: terms of service
TTBOMK: To The Best Of My Knowledge
TTFN: Ta Ta For Now[38]
TTYL: Talk To You Later
TTYT: Talk To You Then
Tweedler: computer geek or someone who plays with themselves at the computer
TYT: Take Your Time
TY: Thank you
TYVM: Thank You Very Much[23]
TB Text back

w8: wait
WAI: what an idiot
WB: welcome back
WDUWTA: what do u wanna talk about?
WEG: wicked evil grin
WG: wicked grin
WTF: what the fuck?; Also "who the fuck?", "why the fuck?", etc. given the context.
WTG: way to go!
WTH: what the heck?, or "what the hell?"
wut: what
w/: with
w/e --- "whatever"
w/o --- "without"

YA RLY: Yeah really
YHBT: You have been trolled
YMMV: Your Mileage May Vary (used as a disclaimer for an opinion)
YNK:you never know
YW: You're Welcome