social media
n. Onlines sites and technologies that enable people to contribute or share content, discuss, rate, or categorize content, or connect or communicate with each other.
Other Forms
When Mena Trott and her husband, Ben, started producing software in 2001, they were 23 years old and unemployed casualties of the dotcom crash in San Francisco.

The couple decided to take a few months out. Mena was a recent convert to the then-new blogging (online diary) craze, so she asked Ben to help her produce a better version of her web log — the aptly named Dollarshort.

Little more than five years later, the Trotts have become Silicon Valley celebrities, the couple at the centre of the ''social media'' phenomenon of which blogging is a part.
—Paul Durman, “Couple make the big time in blogs,” Sunday Times, January 07, 2007
Yahoo is acquiring, a site that allows users and advertisers to create, enter into and judge online contests. The deal is an attempt by Yahoo to bolster its offerings in social media, an area where it has struggled to compete with sites like MySpace and YouTube.
—Miguel Helft, “Yahoo Buys Site for Staging Online Contests,” The New York Times, November 17, 2006
1994 (earliest)
What attracted librarians to the Internet? For some cybernauts, USENET, IRC, and the other social media of the net are the hooks.
—Greg R. Notess, “Telnet explored,” Online, January 01, 1994