Social bookmarking is when people bookmark your site on different bookmarking sites online like del.icio.us, Yahoo! Bookmarks and more. This can help you to get new visitors as they can see other people shared bookmarks on social bookmarking sites. You can read more at http://en.wikipedia.org/wiki/Social_bookmarking
Know about what is social bookmarking and and some big social bookmarking sites at http://en.wikipedia.org/wiki/Social_bookmarking
Social bookmarking site only help you to drive traffic on your site... Here are the list of Social Bookmarking site:: http://www.listible.com/list/social-bookmarking-sites thanks wildstone