Digg.com is one of the most popular Social Bookmarking sites with monthly visitors ranging in millions. It is a technology focused site where stories are chosen ‘digg’ by members rather than editors. The stories with most ‘diggs’ come on top.
Del.icio.us is one of the most used and well known Social Bookmarking sites with monthly visitors also ranging in millions. It allows users to tag, save, manage and share web pages from a central source. Del.icio.us has made huge contribution in improving the way people remember their favorite web pages and share them with other people on Internet.
Reddit.com is another popular Social Bookmarking site with good user base. It is primarily news focused website.
Technorati is Blogger Focused Social Bookmarking site. It provides the facility to search for user generated media (including weblogs) by tag or keyword.