Social Bookmarking
This is a new thing on the internet and is becoming one of the most powerful ways to get traffic. Social bookmarking is defined by wikipedia the following:
A way for internet users to store, organize, share and search bookmarks of web pages. In a social bookmarking system, users save links to web pages that they want to remember and/or share. These bookmarks are usually public, but depending on the service's features, may be saved privately, shared only with specific people or groups, shared only inside certain networks, or another combination of publicness and privateness. The allowed people can usually view these bookmarks chronologically, by category or tags, via a search engine, or even randomly.
http://del.icio.us/
http://www.digg.com/
http://www.blinklist.com/
http://ma.gnolia.com/
http://www.furl.net/
http://www.diigo.com/
http://www.complore.com/
http://www.tallstreet.com/
http://gamingtags.com/
http://indiagram.com/index.php
http://www.goesby.com/
http://teachershare.org/openig/
http://www.chaamp.com/
http://www.a1-webmarks.com/
http://www.tektag.com/
http://www.bookmark.it/
http://www.wirefan.com/
http://www.linkatopia.com/
http://www.optimiz.us/
http://www.web20toolbar.com/