Author Vladimir Nabokov said in a 1969 New York Times interview that "there should exist a special typographical sign for a smile--some sort of concave mark, a supine round bracket."
Now, nearly four decades later, there is just such a typographical symbol-- :-), or :) for the minimalists, and it'd be tough to find a tech-savvy person who hasn't leaned on it. There's also a special typographical symbol for a frown-- :-( -- and one for a cool dude in sunglasses -- B-) -- and one for a wink -- ;-). There's even a typographical sign for wearing a baseball cap-- d=D.