Twitter is a website, owned and operated by Twitter Inc., which offers a social networking and microblogging service, enabling its users to send and read messages called tweets. Tweets are text-based posts of up to 140 characters displayed on the user's profile page. Tweets are publicly visible by default; however, senders can restrict message delivery to just their followers. Users may subscribe to other users' tweets – this is known as following and subscribers are known as followers or tweeps (Twitter + peeps).
All users can send and receive tweets via the Twitter website, compatible external applications (such as for smartphones), or by Short Message Service (SMS) available in certain countries. While the service is free, accessing it through SMS may incur phone service provider fees. The website is based in San Francisco, California. Twitter also has servers and offices in San Antonio, Texas; and Boston, Massachusetts. Twitter, Inc. was originally incorporated in California, but as of 2007 is incorporated in the jurisdiction of Delaware.
Since its creation, in March 2006, and its launch in July 2006, by Jack Dorsey, Twitter has gained popularity worldwide and is estimated to have 190 million users, generating 65 million tweets a day and handling over 800,000 search queries per day.[clarification needed] It is sometimes described as the "SMS of the Internet".