|Social Bookmarking Sites : eAskme|
Search engine not only look for the link that coming to your site from social bookmarking sites but also look for metadata, tags, title, description, categories etc. Social bookmarking also introduce your links to search engines.
Like Stumbleupon and Delicious help search engines in many ways:Faster Indexing Sites: Users bookmark sites launched by their colleagues or friends before a search engine bot can find them.
Deeper Indexing : Many bookmarked pages are deep into sites and sometimes not as easily linked to by others.
Quality : The users bookmark your page, the more relevance and quality your site have.
External Meta Data : People who bookmark sites and tag them with keywords and descriptions.
Co Citation : Social bookmarking sites help users to categories sites, so search algorithms can classify sites easily.
Votes : Same as number of bookmarks, the more votes a page receives on Digg or Reddit, the more popular that that page goes.
Categorization : Categorization help defining the subject of a site.
To help share the wealth of social bookmarking, I have put together a list of 50+ social bookmarking sites, which are very popular.
See this : Best Free Automated Social Bookmarking Software
List of Social Bookmarking Sites