Social Bookmarking

del.icio.us
http://del.icio.us/
Share your bookmarks with others at this leading social bookmarking site.

digg
http://www.digg.com/
Users submit stories for review, but rather than allowing an editor to decide which stories go on the homepage, the users do.

furl
http://www.furl.net/
A social bookmarking site making it easy to save and share favourite web pages.