/ee-moh'ti-kon/ An ASCII glyph used to indicate an emotional state in electronic mail or news. Although originally intended mostly as jokes, emoticons (or some other explicit humour indication) are virtually required under certain circumstances in high-volume text-only communication forums such as Usenet; the lack of verbal and visual cues can otherwise cause what were intended to be humorous, sarcastic, ironic, or otherwise non-100%-serious comments to be badly misinterpreted (not always even by newbies), resulting in arguments and flame wars.
Hundreds of emoticons have been proposed, but only a few are in common use. These include:
:-) "smiley face" (for humour, laughter,
friendliness, occasionally sarcasm)
:-( "frowney face" (for sadness, anger, or upset)
;-) "half-smiley" (ha ha only serious); also
known as "semi-smiley" or "winkey face".
:-/ "wry face"
These may become more comprehensible if you tilt your head sideways, to the left. The first two are by far the most frequently encountered. Hyphenless forms of them are common on CompuServe, GEnie, and BIX; see also bixie. On Usenet, "smiley" is often used as a generic term synonymous with emoticon, as well as specifically for the happy-face emoticon.
It appears that the emoticon was invented by one Scott Fahlman on the CMU bboard systems around 1980. He later wrote: "I wish I had saved the original post, or at least recorded the date for posterity, but I had no idea that I was starting something that would soon pollute all the world's communication channels." [GLS confirms that he remembers this original posting].
As with exclamation marks, overuse of the smiley is a mark of loserhood! More than one per paragraph is a fairly sure sign that you've gone over the line.