We all know the important, other variants of it.
There are many people who have a claim to fame by introducing new and wonderful experiences to the world, but how cool/uncool would it be to be the father of the emoticon?
That's one that Scott E. Fahlman believes he holds, and claims that the first smiley appeared in a posting he made on 19 September 1982 in a bulletin board post at the Carnegie Mellon University.
The smiley appears in a message which says: "I propose the following character sequence for markers :-)."
The idea came about due to messages being posted that were intentionally sarcastic, or fun but offered no way for the reader to know this (aside from an optional disclaimer) which, by the way, also brought about the first incidents of flame wars, which still continue to this day.
Scott explains in his post:
Given the nature of the community, a good many of the posts were humorous (or attempted humor). The problem was that if someone made a sarcastic remark, a few readers would fail to get the joke, and each of them would post a lengthy diatribe in response. That would stir up more people with more responses, and soon the original thread of the discussion was buried. In at least one case, a humorous remark was interpreted by someone as a serious safety warning.
Ah, the Internet.
So, Happy Birthday! :-)