Not Bill Gates, that honor seems to go to Scott Fahlman who history says sent the first smiley on 9-19-1982, though Kevin MacKenzie claims he invented it in 1979.

Yet despite this momentous invention, Fahlman has never made a penny from it. He did not realise what a popular new language he had invented on that September day, he never thought to patent it or even to keep a record of the day himself. :-(
You can read more about it here if you are interested. http://www.guardian.co.uk/Print/0,3858,4504528,00.html