Twitter is an online social media and social networking service owned and operated by American company Twitter, Inc., on which users post and reply to texts, images and videos known as "tweets". Registered users can tweet, like, 'retweet' tweets and direct message (DM), while unregistered users only have the ability to view public tweets. Users interact with Twitter through browser or mobile frontend software, or programmatically via its APIs.
Twitter's origins lie in a "daylong brainstorming session" held by board members of the podcasting company Odeo. Jack Dorsey, then an undergraduate student at New York University, introduced the idea of an individual using an SMS service to communicate with a small group. The original project code name for the service was twttr, an idea that Williams later ascribed to Noah Glass, inspired by Flickr and the five-character length of American SMS short codes. The decision was also partly due to the fact that the domain twitter.com was already in use, and it was six months after the launch of twttr that the crew purchased the domain and changed the name of the service to Twitter. The developers initially considered "10958" as the service's short code for SMS text messaging, but later changed it to "40404" for "ease of use and memorability".
Work on the project started on March 21, 2006, when Dorsey published the first Twitter message at 12:50 p.m. PST (UTC−08:00): "just setting up my twttr". Dorsey has explained the origin of the Twitter title: “...we came across the word "twitter", and it was just perfect. The definition was "a short burst of inconsequential information", and "chirps from birds". And that's exactly what the product was.”
In July, Twitter received a $100,000 Series A funding round led by Union Square Ventures. The app’s popularity started to explode after being heavily promoted by the tech community during the annual South by Southwest conference.
Twitter, Inc. is based in San Francisco, California and has more than 25 offices around the world. By 2012, more than 100 million users tweeted 340 million tweets a day, and the service handled an average of 1.6 billion search queries per day. In 2013, it was one of the ten most-visited websites and has been described as "the SMS of the Internet". By the start of 2019, Twitter had more than 330 million monthly active users.
According to Wikipedia & cnbc.com