Social Bookmarking

Del.icio.us

http://delicious.com/

Delicious is a Social Bookmarking service, which means you can save all your bookmarks online, share them with other people, and see what other people are bookmarking. It also means that we can show you the most popular bookmarks being saved right now across many areas of interest. In addition, our search and tagging tools help you keep track of your entire bookmark collection and find tasty new bookmarks from people like you. Join Now!

YouTube: "Social Bookmarking in Plain English" (3:25)

Shadows

http://www.shadows.com/content/help/whatisshadows.rails

Shadows is the link-sharing website for people. By people. With Shadows, you have the power to discover the web's most fascinating content – the most interesting pages saved, discussed, and rated by you, your friends, and the Shadows community.

Digg

http://www.digg.com/

Digg is a place for people to discover and share content from anywhere on the web. From the biggest online destinations to the most obscure blog, Digg surfaces the best stuff as voted on by our users. You won’t find editors at Digg — we’re here to provide a place where people can collectively determine the value of content and we’re changing the way people consume information online.