Participating in social groups / networking sites are guaranteed to give boost to your traffic. Here is my list of the best social sites sorted by Page Rank:
PR 9
http://www.netscape.com
http://www.slashdot.org
PR 8
http://www.digg.com
http://del.icio.us
http://www.furl.net
http://technorati.com
http://www.stumbleupon.com
http://www.rojo.com
http://www.squidoo.com
PR 7
http://myweb2.search.yahoo.com
http://reddit.com
http://www.fark.com
http://www.43things.com
http://www.mister-wong.de
http://de.lirio.us
http://www.newsvine.com
http://www.blogmarks.net
http://ma.gnolia.com
http://www.simpy.com
(more… 
