From Slate -
When people first started making faces with their keyboards, emoticons were perceived as a tool that would help clarify the tone of online texts. In 1982, Carnegie Mellon University computer science professor Scott Fahlman noticed a problem with the rudimentary online bulletin board his department used to share messages between students, faculty, and staff. Department members liked to make jokes on the forum, but the flat affect of the virtual environment sometimes made it hard to land a punch line. 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,” Fahlman later wrote of the board. “That would stir up more people with more responses, and soon the original thread of the discussion was buried.” On Sept. 19, 1982, Fahlman posted this message:
I propose … 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
:-(
Fahlman is widely credited with inventing the keyboard-rendered facial expression. But as his emoticons gained traction on early computer systems, they took on emotional lives of their own. The frown emoticon that Fahlman pitched to mark a serious post “quickly evolved into a marker for displeasure, frustration, or anger,” Fahlman wrote. “Within a few months, we started seeing the lists with dozens of ‘smilies’: open-mouthed surprise, person wearing glasses, Abraham Lincoln, Santa Claus, the pope, and so on,” each of which conjured a slightly different vibe when deployed in a new context. Fahlman had devised the emoticons to help clarify the meaning of online texts. But he soon realized that the meanings of emoticons themselves were highly subjective. And that was before we started communicating our feelings through endless combinations of tiny, colorful images—pouting cats, silly ghosts, and grinning piles of poo.
http://www.slate.com/articles/technology/users/2015/10/emoticons_and_emojis_as_evidence_in_court.html