Twitter is an American microblogging and social networking service on which users post and interact with messages known as "tweets". Registered users can post, like and retweet tweets, but unregistered users can only read them. Users access Twitter through its website interface or its mobile-device application software ("app"), though the service could also be accessed via SMS before April 2020. Twitter, Inc. is based in San Francisco, California, and has more than 25 offices around the world. Tweets were originally restricted to 140 characters, but was doubled to 280 for non-CJK languages in November 2017. Audio and video tweets remain limited to 140 seconds for most accounts.

Twitter was created by Jack Dorsey, Noah Glass, Biz Stone, and Evan Williams in March 2006 and launched in July of that year. By 2012, more than 100 million users posted 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". As of Q1 2019, Twitter had more than 330 million monthly active users. Twitter is a some-to-many microblogging service, given that the vast majority of tweets are written by a small minority of users.

2006–2007: Creation and initial reaction

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 a short code, 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 9:50 p.m. Pacific Standard Time (PST): "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.

The first Twitter prototype, developed by Dorsey and contractor Florian Weber, was used as an internal service for Odeo employees. The full version was introduced publicly on July 15, 2006. In October 2006, Biz Stone, Evan Williams, Dorsey, and other members of Odeo formed Obvious Corporation and acquired Odeo, together with its assets — including Odeo.com and Twitter.com — from the investors and shareholders. Williams fired Glass, who was silent about his part in Twitter's startup until 2011. Twitter spun off into its own company in April 2007. Williams provided insight into the ambiguity that defined this early period in a 2013 interview:

With Twitter, it wasn't clear what it was. They called it a social network, they called it microblogging, but it was hard to define, because it didn't replace anything. There was this path of discovery with something like that, where over time you figure out what it is. Twitter actually changed from what we thought it was in the beginning, which we described as status updates and a social utility. It is that, in part, but the insight we eventually came to was Twitter was really more of an information network than it is a social network.

Logo and font

Twitter has become internationally identifiable by its signature bird logo, or the Twitter Bird. The original logo, which was simply the word "Twitter", was in use from its launch in March 2006. It was accompanied by an image of a bird which was later discovered to be a piece of clip art created by the British graphic designer Simon Oxley. A new logo had to be redesigned by founder Biz Stone with help from designer Philip Pascuzzo, which resulted in a more cartoon-like bird in 2009. This version had been dubbed "Larry the Bird" specifically named after Larry Bird of the NBA's Boston Celtics fame. Within a year, the Larry the Bird logo underwent a redesign by Stone and Pascuzzo to eliminate the cartoon features, leaving a solid silhouette of Larry the Bird that was used from 2010 through 2012. In 2012, Douglas Bowman created a further simplified version of Larry the Bird, keeping the solid silhouette but making it more similar to a mountain bluebird. This new logo was called simply the "Twitter Bird," and has been used as the company's branding since.[141][144]

On May 30, 2014, Twitter announced, "Starting today, we're rolling out a new font on twitter.com, moving from Helvetica Neue to Gotham".