Digg PR8

Instructions: Submit a link to Digg. If the link/article is popular, it will be shared and rise to the top. You can also publicly share links to websites, but they are nofollow. Type: Bookmarking Site Backlink: http://digg.com  

Plurk

Backlink: http://www.plurk.com Type: Bookmarking Site Instructions: Sign up for an account and create a bookmark for your site.