Twitter is a micro-blogging service that allows users to update with text messages of up to 140 characters in length. Users can also read updates from others by going to users' pages or by "following" them. "Following" allows updates from others to arrive automatically in a feed on a user's Twitter homepage. Twitter functionality is similar to that of Facebook's "status" feature, and both can by synced via Facebook status settings.  

Twitter was founded by Jack Dorsey, Biz Stone, and Evan Williams and launched in early 2006. The site later won a South by Southwest Award in the blog category in March 2007. By mid-2008, Twitter featured over 3M accounts. 

In addition to its functionality as a microblogging service, Twitter also features several social networking elements, including public lists of members who are following a user's updates and those who each user is following (although both of these features may be set to private). Twitter also offers a public profile, a scraping mechanism to find and invite people a user knows through email accounts, and a minimally customizable page.