10. Twitter (319 Million Users)
Starting the list at number ten is microblogging website Twitter with 319 active million users. It is an online news and social networking service where users post and interact with messages, known as ‘Tweets’ restricted to 140 characters. It was launched in 2006 and was founded by Jack Dorsey (CEO), Noah Glass, Biz Stone and Evan Williams. It has been described as “The SMS of the Internet”.