Twenty five years ago, a Carnegie Mellon professor suggested the emoticons as markers for jokes and serious threads on an old school bulletin board system.
Professor Scott Fahlmann said in a post on the bulletin that the
emoticon was to mark a joking thread and the
_ was to marks a serious thread. These were the first emoticons and now they have evolved into graphics, and hundreds of other expressions!
Given today’s sluggish news, I guess this is the most significant event today. Besides, emoticons are mostly the only way we can communicate our emotions on the web.

Yahoo’s emoticon list.