When someone tells you a hilarious joke, you're likely to respond by slapping your thigh, throwing your head back, and chortling with abandon. Should you discover that same joke in your e-mail in-box, however, you're likely to respond with LOL, LMAO, ROTFL, or in the event of extreme mirth, by ROTFLMAO.

If you're new to chat rooms, instant messaging, or e-mail, the above acronyms may seem vaguely official or even intimidating. Relax. Those particular alphabet-soup concoctions simply mean laughing out loud (LOL), rolling on the floor laughing (ROTFL), and laughing my, er, ankles off (LMAO). They're just a few examples of the everyday cyberspace shorthand used to convey laughter and anger, approval and disapproval, love and hate--and everything in between--with a few quick keystrokes.

In addition to acronyms, cyberspace slang also consists of an almost endless assortment of emoticons. An emoticon is a combination of letters, symbols, or numbers that paint a picture (often when viewed sideways). For instance, :) is one of the most popular emoticons, used to represent a smiley face. If :) still doesn't make sense, tilt your head to the left.

Acronyms and emoticons have become the hieroglyphics of a hurried generation. They're informal, often clever, and they save time. But they aren't always appropriate. For instance, sprinkling emoticons throughout a message to a potential employer isn't a good idea--unless the employer is an 18-year-old chat-room habitué. And like any slang, the use of acronyms and emoticons can make those who don't know them feel excluded. So always be considerate about where you use Internet shorthand--and how often.

The following glossary will help you decipher the most commonly used acronyms and emoticons. Plus, we've thrown in a few favorite, exotic examples of each. And because we just couldn't stop ourselves, we've come up with a few pop-culture-inspired acronyms we'd like to see. The possibilities are endless, but if you use your own home-grown acronyms or emoticons, don't forget to explain them to your readers.

afk Away from keyboard

And about to do goodness knows what.

bak Back at keyboard

Having done goodness knows what.

bfn Bye for now

Tells others you're stepping away for an indeterminate amount of time.

Variations: b4n, bbl (be back later).

brb Be right back

Announces a brief absence, as if you're pausing to read a Shakespeare sonnet.

cu See you

The more formal version of cya (See ya).

ltns Long time, no see

A polite way of saying "I forgot you even existed," which could be abbreviated as ifuee.

ttfn Ta ta for now

What Zsa Zsa Gabor might say when exiting a chat room.

Variation: l8tr (later).

gal Get a life

The exact opposite of hand (have a nice day).

kiss Keep it simple, stupid

An impolite way of saying ot (off topic).

pu That stinks

tswc Tell someone who cares

gfete Grinning from ear to ear

Indicates mild amusement in which minimal dental work is displayed.

lmao Laughing my ankles off

The third word can also refer to another body part.

lol Laughing out loud

An appropriate response to a humorous statement. Alas, it doesn't necessarily mean lots of love.

rotfl Rolling on the floor laughing

Use when you couldn't possibly be more amused. Unless you're rotflmao, of course.

aamof As a matter of fact

Though in cyberspace, the fact could just as well be fiction.

afaik As far as I know

Use when you really don't know, but want to appear as if you do.

Variations: afaic (as far as I'm concerned), afaict (as far as I can tell).

btw By the way

A kissin' cousin to fyi (for your information) and fwiw (for what it's worth).

damhikt Don't ask me how I know this

For those obscure factoids your friends tease you for remembering.

eod End of discussion

Use EOD after the 163,456th chat-room message about the new Star Wars trailer.

hth Hope this (or that) helps

imho In my humble (or honest) opinion

Commonly used to preface unsolicited advice, such as "If I were you, I would dump your no-account girlfriend immediately."

Variations: imnsho (in my not so humble opinion), imco (in my considered opinion).

ianalb I am not a lawyer, but...

As in, "IANALB I play one on TV."

j/k Just kidding

Best used when combined with the :) emoticon. For more on the world of emoticons, see Everyday Emoticons.

ot Off topic

A polite way of saying kiss (keep it simple, stupid).

otoh On the other hand

Indicates you were once a member of the high school debate team.

aiamu And I'm a monkey's uncle

Simian slurs are popular everywhere, and cyberspace is no exception.

bbfbbm Body by Fisher, brains by Mattel

Put another way: You have the physique of a Tonka truck and the intellect of Barbie.

cmf Count my fingers

Similar to, though different from, rml (read my lips) or tmt (tally my toes).

dgt Don't go there

Best emphasized by raising your eyebrows, placing one hand on a hip and with the other hand, wagging your index finger warningly--though, of course, your readers will have to imagine that part.

dqydj Don't quit your day job

Or as they say on The Sopranos, 'fagiddaboudit.'

tmi Too much information

An appropriate response to someone who claims their dog likes to eat the furballs their cat coughs up.

bmus Beam me up, Scotty

From Star Trek.

fmdidgad Frankly my dear, I don't give a damn

Clark Gable, Gone with the Wind.

fysbigtbabn Fasten your seat belts, it's going to be a bumpy night

Bette Davis, All About Eve.

gmdts Give my daughter the shot!

Shirley MacLaine, Terms of Endearment.

hlvb Hasta la vista, baby!

Arnold Schwarzenegger, Terminator 2.

mmd Make my day

Clint Eastwood as Dirty Harry, Sudden Impact.

rutus Round up the usual suspects

Claude Rains, Casablanca.

yt2m You talking to me?

Robert De Niro, Taxi Driver.

:) Smile

:( Frown

;) Wink

:o Shocked

?-( Black eye

(((Insert name here))) A cyberhug for the person whose name is surrounded by parentheses

:P Disgusted

The P indicates a protruding tongue.

5:) Elvis

@>--;-- A rose

:-E Bucktoothed vampire

:-F Bucktoothed vampire with one tooth missing

:-.) Cindy Crawford

*<) :o) Clown

O-) Cyclops

:-! Foot in mouth

@:-} Just back from the hairdresser

{:- Wears a toupee

@@@@:-) Marge Simpson

:8) Pig

:-8 Talking out of both sides of your mouth

Hungry for more? The Internet is full of sites that catalog emoticons and acronyms. Here are a few:

AOL subscribers can visit AOL's Computer Center as a starting point. Within the Computer Center channel, click the Fun Stuff tab, then select the Online Fun button, and click the Learn to :) and LOL Online link. You'll find a list of the basic acronyms and emoticons.

NetLingo offers one of the most comprehensive lists of acronyms.

The Correspondence Area of the Primitive Baptist Web Station gives a simple, bare-bones guide to the most common emoticons and acronyms.

A new reference site for lots....thanks to EVA for tipping me off to the dead link that Yewsta be here!

UselessKnowledge.com combines a brief acronym usage history and glossary with a list of the more commonly used emoticons.