According to Wikipedia description of emotions:
The creator of the original ASCII emoticons ๐ and ๐, with a specific suggestion that they be used to express emotion, was Scott Fahlman; the text of his original proposal, posted to the Carnegie Mellon University computer science general board on 19 September 1982 (11:44), was considered lost for a long time. It was however recovered twenty years later by Jeff Baird, from old backup tapes.[7]
19-Sep-82 11:44 Scott E Fahlman :-)
From: Scott E Fahlman
I propose that the following character sequence for joke markers:
:-)
Read it sideways. Actually, it is probably more economical to mark
things that are NOT jokes, given current trends. For this, use
:-(