Twitter

This web page is about twitter is a free social networking and micro-blogging service that allows its users to send and read other users' updates.

Updates are displayed on the user's profile page and delivered to other users who have signed up to receive them. The sender can restrict delivery to those in his or her circle of friends (delivery to everyone being the default). Users can receive updates via the Twitter website, SMS, RSS, email or through an application such as Twitterrific or Facebook.

Twitter has been used as a "social justice tool" to connect groups of people in critical situations.