. Coined by Dale Dougherty of O’Reilly Media in 2004, this lexico-meme is everywhere: Google returns tens of millions of hits; Factiva (a database of thousands of news articles) lists over 1500 citations; the blog search engine Technorati returns nearly 100 000 posts; and O’Reilly hosts an annual Web 2.0 Conference.

Article: http://us.rd.yahoo.com/dailynews/rss/searc....org/jun06/3655
QUOTE
Wikis —collaborative Web sites that allow users to add, edit, and delete content—are pure Web 2.0, with the famous (on some days, infamous) Wikipedia encyclopedia being the canonical example. Allowing users that much control is an experiment in radical trust.