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This article discusses general features of Internet slang. For detailed usages, see List of Internet slang.
Internet slang is slang which Internet users have coined and promulgated. Such terms typically originated with the purpose of saving keystrokes: many use the same abbreviations in text messages. The terms often appear in lower case, with capitals often reserved for emphasis: The pronoun "I", for example, often appears simply as "i".

To avoid misapprehension and clarify the author's intent, netizens may use emoticons. Emoticons (or smilies) such as may be used both genuinely and sarcastically; for example the emoticon, can express either genuine amusement and a sense of fun, or a negative sarcastic comment on something. Deciphering and understanding what was written per se versus the author's intent is part of the Internet's attraction and enjoyment. Like most jargon, Internet slang aggrandizes author and reader, causing them to appear as having specialized knowledge of an already complex medium.

Internet slang perhaps has a higher learning curve than face-to-face slang, as face-to-face slang can often be deciphered from the context of the facial expressions, body language, and tone of voice.

The vocabulary of Internet slang (or chatspeak or netspeak) draws from many different sources — typically environments that placed value on brevity of communication. Some terms, such as FUBAR have roots as far back as World War II.[1] Other terms come from more recent forms of communication, such as TTY and IRC.

Chat acronyms originally developed on pre-Internet bulletin board systems. A handful (for example, ASAP, PO'ed) far pre-date computers. The three-letter acronym remains one of the most popular types of abbreviation in computing and telecom terminology and slang. Similar systems have since come into use with users of text-messaging wireless telephones.

With the rise of instant messaging services (ICQ, AOL, and MSN, among others) the vocabulary has expanded dramatically.

Aside from instant messaging programs another realm full of online languages exists: the Internet gaming world. One of the most popular forms of video game slang has become known as H4x0r (Haxor, meaning hacker) or as 13375p34k (in leetspeak). For parents today, learning the online language can play an important role in maintaining the online safety of children. An article produced by Microsoft may help parents begin to understand some of the things their kids say in-game. (Many of the more knowledgeable "online gamers" consider this article unhelpful, especially for Microsoft's attempts to interpret 1337 speak.)

Note that many more serious internet users regard leetspeak as a trademark of people who don't know what they're doing. In these circles, leetspeak is almost always used sarcastically if at all. Such people may also label the use of leetspeak, excessive use of abbreviations, and incorrect spelling and grammar as simply rude, and a sign of laziness. In addition, sometimes chatspeak or leet can be so illegible that it becomes an annoyance for those who wish to read it.

Sometimes users make up Internet abbreviations on the spot, therefore many of them can seem confusing, obscure, whimsical, or even nonsensical. This type of on-the-spot abbreviating leads to such things as: OTP (on the phone) or the less common, OPTD (outside petting the dog). Another feature common to Internet communication involves the truncation and morphing of words to forms that users can type more readily. Examples of this include:

addy — "Address" (plural: "addys")
pic — "Picture" ("pics", "pix" or "piccies" for plural)
proggy — "Computer program"
prolly — "Probably" (also "probs")
sig — "Signature" (also "siggy")
asl? — "Age/Sex/Location?" (also "a/s/l?"; a phrase often used in internet chat rooms)
The form "teh" offers a special case of this transformation. This originated as a corruption of "the", and often pops up spontaneously when typing fast. So common has it become, in fact, that it has made the jump to deliberate usage. Typically it occurs in situations where the writer presents as self-consciously enthusiastic, mimicking the less-grammatical Internet newbie: "That movie was teh suck!!", "The fight scene with all the Agent Smiths was TEH AWESOME", etc. It occurs most commonly in "teh suck/orz", "teh lame," and "teh cool". Jeff K. of Something Awful popularized this sarcastic usage.

Similarly, netizens may use the word "liek" or "leik" as sarcastic misspellings of the word "like", as in "I LIEK PIE". It often implies an insult to one's intelligence and/or typing ability. "Liek" is also often used as a geeky way of typing the preposition like, for example in the phrase "...and I was liek...".

Internet abbreviations evolve and change continually. Online games provide a good place to observe language variation in use. Often, people uninterested in computer programming do not understand the more classically "nerdy" phrases like "2B||!2B" (which means "to be, or not to be"), thus such usages become useless or appear only in minority forums.

From the days of FIDO mail when many computers ran DOS we find <G> meaning "Grin", <BG> "Big Grin", <VBG> "Very Big Grin", and of course <VBSEG> "Very Big Shit-Eating Grin". Lower-case variants (<g> and so on) are also used.

Common disclaimer phrases (sometimes called "parentheticals") also often contract into acronyms — they tend to occur at certain points in a sentence, which can facilitate decoding. By far the most common of these are "lol", "lmao", "rofl", "omg", "brb" and "wtf". This is a fraction of the full list, but some of these disclaimers include:
1337: see L33t (awesome or great)
AFK: away from keyboard
AFAIK: as far as I know
ASAP: as soon as possible
ATM: at the moment
Bai2u: 'bye to you' goodbye
BBIAB: be back in a bit (used to express a longer time of absence than with brb)
BBL: be back later
BBS: be back soon
BRB: be right back or bathroom break (very commonly used)
BTW: by the way
Bump: used in forums to bring a post to the top of the forum list (a common backronym for "bring up my post")
CYA: see ya, or see you later (also CU) (or, less commonly and depending on the context, cover your ass)
DMY: don't mess yourself (used to tell someone they are overreacting, seen on The Simpsons as a spoken abbreviation)
DW: Don't Worry
F2P: free to play
FFS: for fuck sake
FTL: for the lose (used to dislike something)
FTW: for the win (used to express enthusaism or approval) (Less commonly known as "Fuck the world")
FU: Fuck you
FYI: for your information
FYSIWALOL: finding your saying interesting without actually laughing out loud
G2G or GTG: got to go or good to go
GG: good game or good god
GF: Good Fight
GJ: Good Job
GL: good luck
GN8: good night
GTH: go to hell
GOOMH: Get Out Of My House
GLLN: Got Laid Last Night(?)
Hai2u: 'hi to you' hello
HTH: hope that helps or happy to help
IANAL: I am not a lawyer (used when offering amateur commentary on a legal case)
IAS: I am smiling (not quite "lol")
IDK: I don't know
IIRC: if I recall/remember correctly
IMO: in my opinion
IMHO: in my humble/honest opinion (derived from IMO or vice-versa)
IRL: in real life
JIC: just in case
JK: just kidding
JW: just wondering
KIT: keep in touch
KK: okay
kthxbye: Shorter, and faster, way of saying "Okay. thank you. Good bye".
Lag: where a connection is not as fast as others making the game lag behind
L33t: elite
LFG: looking for group (used mostly in MMORPGs)
LFT: looking for team (used mostly in MMORPGs)
LOL: laugh out loud
LMAO/LMFAO: Laugh my (fucking) ass off
L2P: learn to play
LYLAS: love you like a sister
nOOb: Newbie, often one who dies alot in their first few times in games online
N1: nice one
NP: no problem
NS: nice shot
NSS: no shit sherlock
NT: nice try
NVM: nevermind
NSFW: not safe for work (often used as a warning that a link contains racy or pornographic images)
NWS: not work safe
OAC: Only At Crooms
OMG: oh my god
OMFG: Oh My Fucking God/Sh
OMGWTFBBQ: combines the terms OMG, WTF, and BBQ. (can also be used as a mockery of newbies who express surprise at commonly known facts, or in self deprecation)
OMW: on my way (usually used in ORPGs)
OH NOES: oh no
OP: original post/original poster (referring to the first post in a thread)
OTOH: on the other hand
ORV: orita vengo (used in Spanish)
P2P: pay to play, player to player, or peer to peer
PK: Player kill
PVP: Player vs. Player
PVE: Player vs. Enemy/Environment
PWN: (p)owned. Usually refering to someone in a video game being decidely beaten by another player.
PEBKAC: problem exists between keyboard and chair
PO'd: pissed off
QFT: quoted for truth
QQ: cry more (meant to look like eyes with tears dripping from them)
QT: cutie
RE: returned or back or rematch
RM: remake
RIFK: See ROFL. Originally a typing error of ROFL, it is now puposely used in place of ROFL. Some, however, refer to it as Rolling In the Floor Kicking (But you can't roll IN a floor, can you?). Others say it is Rolling In teh Funneh Kookies (which doesn't make sense either).
ROFL: rolling on floor laughing
ROLF: rolling on laughing floor
ROFLCOPTER: retardation of ROFLMAO
ROLFCOPTER: even bigger retardation of ROFLMAO (rolling on "laughing" floor)
ROTFL: rolling on the floor laughing
ROTFLM(F)AO: rolling on the floor laughing my (fucking) ass off
RTFM: read the fucking manual
SGTM: Silently giggling to myself
SFW: safe for work
SIF: As if
SU: shut up
STFU: shut the fuck up
STFUPPERCUT: shut the fuck upper cut!
STHU: shut the hell up
TBA: to be added or to be announced
TBH: to be honest
TTYL: talk to you later
TTYS: talk to you soon
TY: thank you
TYVM: thank you very much
THX: thanks
YW: you're welcome
W/E(W\E)(W.E)(WE): whatever
WD: Well done
WS: work safe
WTH: what the heck/hell
WTB: want to buy
WTG: way to go
WTF: what the fuck
WTS: what the shit or want to sell
WTT: want to trade
WTV: watching tv
WUU2: what you up to
WU@: what you at
ZOMG: variant of OMG, taken from a typo of hitting the 'z' next to the left shift (typically when very excited)