Overview
Twitter began as a short-message service inside podcasting company Odeo in 2006. It became a public social network where people followed accounts, posted updates, and shared news. The service is now called X and remains in operation.[1][2]
Elon Musk acquired Twitter in 2022 and renamed it X. In March 2025, his AI company xAI acquired X in an all-stock transaction. SpaceX acquired xAI, including X, in 2026. These were changes in ownership among businesses under Musk's control, not the closure of the social platform.[3][4]
Founding Story
Twitter emerged from an Odeo brainstorming session. Jack Dorsey described developing an SMS-based way for a person to share a status with a group. Noah Glass, Biz Stone, and Evan Williams were also involved in the company's early formation. Dorsey's first message was sent on March 21, 2006; the service opened to the public that July.[1][5][6]
The original short-post format followed the constraints of mobile text messaging. Users could follow accounts and read updates from others, while conventions such as hashtags and reposting helped people organize and spread public conversations. Twitter's visibility grew at the 2007 South by Southwest conference.[5][1]
Timeline
- 2006: The service began at Odeo and opened to the public.[1]
- 2010: Twitter introduced promoted tweets and trends, beginning its advertising business.[13]
- 2013: Twitter became a public company.[7]
- 2017: Twitter expanded the post limit to 280 characters for most languages after a test.[14]
- 2021: Twitter reported an average of 217 million monetizable daily active users in the fourth quarter.[8]
- 2022: Musk acquired Twitter. An SEC filing listed a16z among investors who had committed financing to the proposed transaction.[9][10]
- 2023: Twitter was renamed X.[3]
- 2025–2026: xAI acquired X; SpaceX then acquired xAI, including X.[3][4]
What They Built
Twitter combined short posts with a network of accounts. Following a person or organization brought their updates into a reader's stream. Replies, mentions, hashtags, and reposts let a message reach people beyond the original sender's followers. The product moved beyond its SMS origins as the web and smartphones became its main surfaces.[5]
Twitter began selling promoted tweets in search and promoted trends in 2010, then expanded promoted tweets into timelines and mobile apps. By late 2013, its filing said over 75% of advertising revenue came from mobile devices. Advertising made the free network a business, while requiring Twitter to place paid messages alongside user posts.[13]
In 2017, Twitter expanded the 140-character limit to 280 for most languages. It said a test found only 5% of posts exceeded the old limit, addressing its concern that longer posts would overwhelm timelines.[14] The service later added features including paid subscriptions. X's current help center lists multiple Premium tiers and notes that availability and prices vary by market. It is still an operating product, although its policies and ownership have changed.[11][2]
Market Position
Target Customers
The network served readers, individual posters, publishers, public figures, and advertisers. Its value to each group depended partly on the presence of others: a reader needed accounts worth following, while a publisher sought an audience.
Market Size
Twitter's 2021 annual report reported 217 million average monetizable daily active users for the quarter ended December 31, 2021. That company-defined measure is a historical quarterly average, not current X usage.[8]
Competition
X competes for attention with other social platforms. A new entrant must attract both readers and people producing timely posts. X's existing network and real-time conversation make a generic short-post clone a difficult starting point, but the public data here does not establish a current share of social usage.
Business Model
Twitter's 2021 filing said it generated substantially all advertising revenue from promoted products. X also sells paid Premium subscriptions, with pricing dependent on location and applicable taxes. Its historical advertising disclosures should not be treated as current revenue figures.[8][2]
Traction
Twitter's 2021 annual report showed the scale of its network before the take-private: average monetizable daily active usage was 217 million in the fourth quarter, up 13% year over year. The metric measures accounts Twitter could show ads to under its definition; it does not count all registered accounts.[8]
Outcome and evolution
A public network went private
Musk acquired Twitter in October 2022 after an agreement and litigation over the transaction. A May 2022 SEC filing listed a $400 million equity commitment from AH Capital Management, a16z's management company, for the proposed acquisition. A commitment is a financing obligation subject to its terms; the filing alone is not a separate proof of the final amount funded.[9][10]
Common-control combinations changed the ownership structure
In March 2025 Musk announced that xAI had acquired X in an all-stock deal. Both were privately held and controlled by Musk. Associated Press reported that xAI already used data from X posts to train models and that X users could access its Grok chatbot. SpaceX announced its acquisition of xAI in February 2026; a SpaceX prospectus describes that transaction as including X.[3][12]
The transactions placed a social network, AI business, and space company in the same ownership group. They do not establish that the social service ceased operations, nor do they show an independent market price for X separate from the announced transaction's stated valuation.
Key Lessons
- A format can become a network. Short messages made posting easy, while following and reposting connected those messages to an audience.
- Usage and economics need separate measures. Twitter's historical daily-user figure shows reach; its filing separately explains the advertising business that monetized that reach.
- Ownership changes do not define product status. X continued after the take-private, rebrand, and combinations with xAI and SpaceX.