On September 10, 2002 Scott Fahlman introduce to the first time, the use of smiley on CMU CS general bboard and was retrieved by Jeff Baird from an October 1982 backup tape of the spice vax (cmu-750x).
Here is Scott's original post:
19-Sep-82 11:44 Scott E Fahlman :-)
From: Scott E Fahlman
I propose that the following character sequence for joke
Read it sideways. Actually, it is probably more economical to
things that are NOT jokes, given current trends. For this, use
Reference: The First Smiley :-)