Did you try http://www.social-bookmarking-sites-l...

It has a good list

Hmm thanks for list [seo]

Can you please change the term seo to your real name. It will be great to call you on your name instead of seo.

I am unable to change the username. Can you tell me how to do it.

Actually username can't be changed once created. However you can create another account using your Facebook, Twitter or Direct form to register a new username with your real name.

Here is list
From PR6-PR0
http://adf.ly/6RpwZ

Source: http://sdhacks.blogspot.com