X

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Elon Musk chose a white letter X on a black background as the brand for the microblogging service X. The former Twitter brand, a white bird on a sky blue background, is also shown.

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X, formerly Twitter (2006–2023), is a social media and microblogging service where users share short posts of no more than 280 characters. The site was influential in shaping politics and culture in the early 21st century.

The successor to Twitter, X Corp., is a wholly owned subsidiary of X Holdings Corp., which is owned by the artificial intelligence company xAI. In 2026, xAI became a subsidiary of the publicly traded aerospace company SpaceX, which is controlled by South African–born American entrepreneur Elon Musk.

In April 2022, Musk signaled plans to merge Twitter with one of his corporate entities, X Holdings, in a filing with the Securities and Exchange Commission. After Musk completed the deal to acquire Twitter in October 2022, he took steps to merge Twitter with X and rename the company.

However, Musk used a different company, X Corp., which he registered in Nevada in March 2023, to merge with Twitter. He also registered two other companies in Nevada in the same month: X Holdings Corp. (the new parent of X Corp.) and X.AI Corp (commonly known as xAI). The merger between Twitter and X Corp. took place in April 2023, and Twitter ceased to exist as a company, according to a court filing in California.

Today, X is primarily run as a social media service, although Musk has said he wants to turn it into an “everything app” that can be used for shopping, financial transactions, and more, similar to China’s WeChat. In February 2026, Musk announced that his space exploration company SpaceX had acquired xAI, consolidating assets into one combined company ahead of a planned initial public offering (IPO).

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Twitter cofounders Biz Stone (left) and Evan Williams, 2009.

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Twitter emerged from the podcasting venture Odeo, which was founded in 2004 by Evan Williams, Biz Stone, and Noah Glass. (Williams and Stone had previously worked at Google, and Williams created the popular Web authoring tool Blogger.) Apple announced in 2005 that it would add podcasts to its digital media application iTunes. Odeo’s leadership felt that the company could not compete with Apple and needed a new direction.

Odeo’s employees were asked about any interesting side projects they had, and engineer Jack Dorsey proposed a short message service (SMS) on which one could share small, blog-like updates with friends. Glass proposed the name Twttr. Dorsey sent the first message (“just setting up my twttr”)—called a tweet—on March 21, 2006; the completed version of Twitter debuted July 15, 2006.

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March 21, 2006: “just setting up my twttr.”

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Seeing a future for the product, Williams, Stone, and Dorsey bought out Odeo and started Obvious Corp. in October 2006 to develop it further. Interest in the service sharply increased after it was presented at the South by Southwest music and technology conference in Austin, Texas, in March 2007.

The following month, Twitter, Inc. was created as a corporate entity after an infusion of venture capital, and Dorsey became Twitter’s first chief executive officer (CEO). In 2008, Williams ousted Dorsey as CEO, and two years later Williams was replaced as CEO by Chief Operating Officer Dick Costolo.

Actor Ashton Kutcher beat CNN in a widely publicized race in April 2009 to become the first Twitter user to reach one million followers. The event highlighted Twitter’s emerging role as a social network built around individual personalities as much as institutions. Although celebrity “e-watching” remained a significant draw to the service, businesses soon began sending tweets about promotions and events. Political campaigns discovered the value of Twitter as a communication tool.

During the 2008 U.S. presidential election, Barack Obama far outpaced his opponent, John McCain, in the social media sphere, amassing almost four times as many Myspace friends and more than 20 times as many Twitter followers. The gap signaled how important a social networking presence would become in future political campaigns..

On January 15, 2009, a tweet by commuter ferry passenger Janis Krums broke the story of the successful water landing of US Airways flight 1549 on the Hudson River in New York City. A hastily snapped camera phone image of passengers disembarking the half-submerged aircraft established Twitter as a breaking news source.

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Twitter cofounder Jack Dorsey, 2018.

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In June 2009, state media in Iran reported that President Mahmoud Ahmadinejad had secured an easy victory. Supporters of opposition candidate Mir Hossein Mousavi took to the streets in a series of demonstrations that provoked a government crackdown, in which some demonstrators were injured or killed. The hashtag #IranElection became one of the most-followed topics on Twitter as Mousavi supporters coordinated protests and posted live updates from Tehran.

Following the earthquake that struck Haiti in January 2010, Twitter reaffirmed its role as a powerful tool for sharing information. The Red Cross used the service to promote a mobile giving campaign that raised millions of dollars in donations by text messaging.

In 2009, Twitter introduced a blue check mark to verify the identities of public figures and organizations. The move came after St. Louis Cardinals manager Tony La Russa sued the company over a parody account. In response, Twitter began verifying accounts belonging to celebrities, public officials, and government agencies.

In September 2013, Twitter filed for an initial public offering and announced the move in a tweet. The IPO took place in November and raised $1.8 billion, giving the company a market capitalization of $31 billion. Twitter traded under the ticker symbol TWTR.

In October 2015, cofounder Jack Dorsey returned as CEO. Although Twitter continued to grow in popularity, it still wasn’t profitable, so the company introduced new features to increase user engagement. That same month, it launched Moments, a curated feed of tweets organized by topic. Moments was folded into the short-lived Explore tab in 2017.

In March 2016, Twitter replaced its purely chronological timeline with an algorithmic feed that prioritized tweets based on popularity and user behavior. The company finally became profitable in the last quarter of 2017, when it reported 330 million monthly users. Even so, it posted positive earnings in only two of its eight years as a public company.

Also in 2017, Twitter doubled its character limit to 280 from 140. In early 2019, it stopped reporting monthly users and switched to a new metric: monetizable daily active users (mDAUs), meaning users who see ads.

In November 2020, Twitter introduced Fleets—temporary posts that disappeared after 24 hours—modeled after Stories on Snapchat (SNAP) and Meta Platforms’ (META) Instagram and Facebook. The feature never caught on and was discontinued in August 2021.

Twitter launched Spaces, a live audio feature, in May 2021 for accounts with more than 600 followers. Later that year, in November, Dorsey stepped down again and was replaced by chief technology officer Parag Agrawal.

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Elon Musk’s takeover of Twitter, later renamed X, reshaped the service’s identity and direction.

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In 2022, Twitter announced Elon Musk would acquire it and that Musk was to become the company’s sole owner. But, in an apparent case of buyer’s remorse, three months later Musk announced that he would be withdrawing his bid for Twitter, citing concerns over bot accounts and claiming that the company was in “material breach of multiple provisions” of the purchase agreement.

Bret Taylor, the chair of Twitter’s board of directors, responded by saying that the company was “committed to closing the transaction on the price and terms agreed upon with Mr. Musk.” By then, Twitter shares had declined roughly one-third from Musk’s proposed purchase price. In July 2022, Twitter sued Musk to force him to buy the company, and in September 2022 Twitter’s shareholders voted to accept Musk’s offer.

Musk bought Twitter in October 2022 for $44 billion at his original proposed price of $54.20 a share. Among his first acts as Twitter’s owner were to lay off about half the company and allow users to purchase the blue check mark verification for $8 a month.

In April 2023, Twitter was renamed X. With Twitter no longer in existence, the ticker symbol (TWTR) was delisted on major stock exchanges. X became a private company controlled by Musk.

In May 2023, Musk hired veteran advertising executive Linda Yaccarino as CEO, giving her responsibility for the company’s business operations while he focused on product development and technology. She previously had led advertising at NBCUniversal and stood out as one of the few major industry figures who pledged to keep running ads on Twitter after Musk acquired it, even as other advertisers pulled back.

As CEO, Yaccarino worked to rebuild relationships with advertisers, navigate Musk’s unpredictable leadership, and promote X’s shift toward integrating artificial intelligence (AI) through his new company, xAI.

In March 2025, Musk said he had sold X to xAI in an all-stock deal that valued X at $33 billion. Although X and xAI are technically separate businesses, their operations and technical teams have become more closely intertwined.

Yaccarino stepped down in July 2025, giving no reason for her departure. Her resignation followed ongoing advertiser concerns and repeated public controversies, including antisemitic comments shared by Grok, X’s AI chatbot, just days earlier that sparked outcry. During her tenure, she defended Musk’s decisions in lawsuits and meetings with lawmakers and said most top advertisers had returned to X—though many hadn’t restored previous spending levels.

After the acquisition, Musk disbanded Twitter’s content moderation team and reinstated many banned accounts, including the one belonging to President Donald Trump, which had been suspended after the U.S. Capitol attack on January 6, 2021. Advertising revenue fell sharply after many companies withdrew their ads, and the Twitter identity was stripped from the service. Tweets became known as posts.

In 2023, X and Musk became embroiled in controversy about how many of his changes have made the service a less reliable information resource. One accusation of misinformation is related to the Israel-Hamas War. European regulators issued a warning to Musk and insisted that he respond with how he is battling illegal misinformation on the website.

Musk has claimed to be a “free speech absolutist” in the past, but some of his decisions have had the effect of throttling posts critical of him and the changes to the platform. Criticisms of X under Musk include concerns that hate speech and violence have been more likely to spread, especially with Musk’s move to change how the “block” and “mute” functions work. He has been accused of enabling cyberbullying by changing how these functions work.

Twitter, once one of the most recognizable names in social media, has been replaced by X. Whether the site is seen as a largely unmoderated “town square” or a reliable source of information remains up for debate. Competing services have so far struggled to match Twitter’s influence. As of 2026, it’s still unclear whether Musk’s vision of an “everything app” will materialize, whether such a service would face regulatory hurdles, or how X will evolve as part of a publicly traded corporate group that also includes xAI and SpaceX.