+1

As a telephone number, +1 represents the North American Numbering Plan - which covers much of the English-speaking Caribbean as well as Canada, the US and its possessions. It's much like the "+1" concept in event invitations - you want to invite Canada, but they won't come unless you let them bring their loud, obnoxious neighbor as a "+1".

Giving credit for something, usually a line of dialogue, use of a word in a particular situation, or a concept. Giving props to the person you just quoted. Popularized in 90's Usenet newsgroup lingo, still used occasionally by old schoolers in the know.

The IQ of President George Bush.

Used by forum posters when a person agrees with a point. Sometimes used incorrectly when referring to one's postcount going up.

A term originally created by a sergeant with the Los Angeles Police Department SWAT Team. Designed as a reminder that in fact you only have "one ass to risk"(1 as-te-risk), so you'd better be careful.

A sideways-style text smiley. The colon represents the eyes, and the one represents a straight-forward mouth. The line's dent(s) at the tip(s) represents the curve of a lip.
It's used to show that you're neutral when it comes to what you're saying or reading. Not happy. Not upset. Just regular.

Happens when a careless internet queen gets excited and types too much.