Top dofollow social bookmarking websites

One of the ways to promote your website or blog and gain additional visitors is to submit your URL to social bookmarking websites. Now one may ask, what is social bookmarking? According to Wikipedia:

Social bookmarking is a method for Internet users to store, organize, search, and manage bookmarks of web pages on the Internet with the help of metadata. In a social bookmarking system, users save links to web pages that they want to remember and/or share. These bookmarks are usually public, and can be saved privately, shared only with specified people or groups, shared only inside certain networks, or another combination of public and private domains. The allowed people can usually view these bookmarks chronologically, by category or tags, or via a search engine.

The following is list of top dofollow social bookmarking websites, ranked according to traffic via Alexa Ranking.