Twitter is an online social networking service and microblogging service that enables its users to send and read text-based posts of up to 140 characters, known as "tweets". It was created in March 2006 by Jack Dorsey and launched that July. The service rapidly gained worldwide popularity, with over 140 million active users as of 2012, generating over 340 millions tweets daily and handling over 1.6 billion search queries per day. It has been described as "the SMS of the Internet." Unregistered users can read the tweets, while registered users can post tweets through the website interface, SMS, or a range of apps for mobile devices. Twitter Inc. is based in San Francisco, with additional servers and offices in New York City. The Twitter website is one of the top ten most visited on the Internet.