Total Users : 200 million
Alexa Ranking : 9
Twitter is an online social networking and microblogging service that enables its users to send and read text-based posts of up to 140 characters, informally known as "tweets".
Twitter was created in March 2006 by Jack Dorsey and launched in July of that year. Twitter rapidly gained worldwide popularity, with 200 million users as of 2011, generating over 200 million tweets and handling over 1.6 billion search queries per day. It is sometimes described as the "SMS of the Internet".
Twitter Inc., the company that operates the service and associated website, is based in San Francisco, California, with additional servers and offices in San Antonio, Texas, Boston, Massachusetts, and New York, New York.
Twitter has been compared to a web-based Internet Relay Chat (IRC) client.
Tweets are publicly visible by default; however, senders can restrict message delivery to just their followers. Users can tweet via the Twitter website, compatible external applications, 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.
Users may subscribe to other users' tweets – this is known as following and subscribers are known as followers or tweeps.
Twitter allows users the ability to update their profile by using their mobile phone either by text messaging or by apps released for certain smartphones / tablets.
In a 2009 Time essay, technology author Steven Johnson described the basic mechanics of Twitter as "remarkably simple":
As a social network, Twitter revolves around the principle of followers. When you choose to follow another Twitter user, that user's tweets appear in reverse chronological order on your main Twitter page. If you follow 20 people, you'll see a mix of tweets scrolling down the page: breakfast-cereal updates, interesting new links, music recommendations, even musings on the future of education.
In June 2008, Twitter launched a verification program, allowing celebrities to get their accounts verified. Originally intended to help users verify which celebrity accounts were created by the celebrities themselves, they have since been used to verify accounts of businesses and accounts for public figures who may not actually tweet but still wish to maintain control over the account that bears their name.