6th place is acquired by Wikipedia, free content Internet encyclopedia supported and hosted by the non-profit Wikimedia Foundation. Jimmy Wales and Larry Sanger lunched Wikipedia on January 15, 2001. The visitor of this site can access all the articles of this site and those who follow its rules can edit most of its articles. Wikipedia is the most popular and largest encyclopedia for it’s large number of article and general reference work in the world of Internet. Wikipedia is most popular site among all people in all field like Professors, Students, Researcher, Article Writer, Scientist, Author etc and this site also provide facilities to it’s user to build their own books with articles they have collected from wikipedia.

According to Alexa as of 27/03/2015, daily page viewed 680 million hits per day and 200 million visitor visit this site per day.