Just few of them. If you know more, post here
http://www.spurl.net
http://www.furl.net
http://www.simpy.com
http://www.feedmelinks.com
http://www.linkroll.com
http://www.citeulike.org
http://del.icio.us
http://www.connotea.org
http://www.rojo.com
http://www.gibeo.com
http://frassle.rura.org
http://www.digg.com