For the Twitter feature called "timeline", see Twitter feed.
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The history of Twitter, later known as X, can be traced back to a brainstorming session at Odeo.
Major events
Time period
Key developments at Twitter
March 2006 – March 2007
Twitter launches as a product of parent company Odeo. It grows slowly until March 2007, where usage grows dramatically after it is showcased at the South by Southwest Interactive (SXSW) conference.
April 2007 – October 2008
Twitter grows rapidly under CEO Jack Dorsey, completing two funding rounds and launching official support for hashtags.
October 2008 – October 2010
Jack Dorsey steps down, and Evan Williams takes over as CEO. Twitter raises money, gets celebrity endorsements and publicity, and continues to grow rapidly. The first tweet from space occurs during this period. Twitter also announces that it will start allowing for advertising in the form of promoted tweets – "ordinary tweets that businesses and individuals want to highlight to a wider group of users."
October 2010 – October 2013
Evan Williams steps down as CEO, and Dick Costolo takes over.
October 2013
Twitter announces plans and files relevant legal documents in October 2013 so as to go public. In November 2013, it has its initial public offering. Post-IPO, the company's pace of acquisitions increases dramatically.
November 2014 – present
With the launch of features such as Instant Timeline, While You Were Away, Quality Filter, Curator, and Moments, Twitter diversifies beyond just being a reverse chronological stream of tweets by people you already follow.
July 2015 – present
Dick Costolo departs Twitter and Jack Dorsey assumes the role of interim CEO. Commentators note that the "founder's instincts" are influencing the product's new direction.
Odeo's podcasting service is released, with very little public response.
2006
February 26–27
Creation
Jack Dorsey, Noah Glass, Evan Williams and Biz Stone discuss the idea of using text messaging to share statuses, and decide to work on the project. The original idea is attributed to Jack Dorsey, and called the status concept.[4]
2006
Early March
Creation
The name Twitter (spelled twttr at the time and using a green site logo[5]) is chosen for the service. The idea for the name is attributed to Noah Glass.[6][7]
2006
March 21
Creation
Twitter is officially set up and Jack Dorsey sends the first tweet.[8]
2006
July 15
Media coverage
Noah Glass tells Om Malik about Twitter (then called twttr), and Malik writes what appears to be the first ever news coverage of Twitter,[9] and several people, including Malik himself, have commented on the accuracy (or lack thereof) of its predictions from the perspective of hindsight.[10][11][12]
2006
August 3
Usage
Twitter users tweet about a mild (4.4 on the Richter scale) earthquake in California. The event helps Twitter's team see the potential of Twitter as a way for many people to contribute to the reporting of a live event, each from his or her own vantage point.[13]
2006
September
Creation
Twttr renames itself Twitter after purchasing the Twitter.com domain name.[14]
2006
September
Userbase
Twitter attempts to have a grand launch at the Love Parade, but gets very little traction there, with only 100 new signups.[15]
2006
October
Financial/legal and company operation
Biz Stone, Evan Williams, Dorsey, and other members of Odeo, form Obvious Corporation and acquired Odeo, together with its assets—including Odeo.com and Twitter.com—from the investors and shareholders.[16]
Twitter announces that it has closed a funding round led by Fred Wilson of Union Square Ventures.[22] The five-million-dollar round values Twitter at $20 million.[23]
Twitter reschedules planned downtime for maintenance so as not to conflict with a large planned protest in Iran.[35] Because a US State Department official had emailed Twitter about the planned protest, newspapers speculate that Twitter rescheduled its downtime because of pressure from the US government.[36][37][38]
Twitter announces that it will start allowing for advertising in the form of promoted tweets – "ordinary tweets that businesses and individuals want to highlight to a wider group of users."[41][42][43]
Implementation of hash-bang fragment URLs and AJAX-based page loading. Replaced by JavaScript PushState in early 2012 due to problems with compatibility and shareability.[45][46]
Twitter tests a new homepage and phased out the "Old Twitter."[50] However, a glitch came about after the page was launched, so the previous "retro" homepage was still in use until the issues were resolved; the new homepage was reintroduced on April 20.[51][52]
2011
July 5
Acquisition
Twitter acquires BackType, a real-time social analytics platform.[53][54]
2011
September 8–9
Financial/legal
Twitter closes its Series G round, raising $800 million at a $8 billion valuation. Of the $800 million, $400 million buys off shares from existing investors and the remaining $400 million goes to the company.[55][56]
2011
December 8
Product
Twitter overhauls its website once more to feature the "Fly" design, which the service says is easier for new users to follow and promotes advertising. In addition to the Home tab, the Connect and Discover tabs are introduced along with a redesigned profile and timeline of Tweets. The site's layout is compared to that of Facebook.[57][58]
2012
February 21
Product
Twitter announces a partnership with Russian search engine Yandex. Yandex, a Russian search engine, finds value within the partnership due to Twitter's real time news feeds. Twitter's director of business development explained that it is important to have Twitter content where Twitter users go.[59]
2012
March 21
Userbase
Twitter celebrates its sixth birthday while also announcing that it has 140 million users and sees 340 million tweets per day. The number of users is up 40% from their September 2011 number, which was said to have been at 100 million at the time.[60]
2012
April
Company operation
Twitter announces that it is opening an office in Detroit, with the aim of working with automotive brands and advertising agencies.[61] Twitter also expanded its office in Dublin.[62]
2012
June 5
Product
A modified logo is unveiled through the company blog, removing the text to showcase the slightly redesigned bird as the sole symbol of Twitter.[63]
Twitter acquired a video clip company called Vine that launches (later) in January 2013.[65][66] Twitter released Vine as a standalone app that allows users to create and share six-second looping video clips on January 24, 2013. Vine videos shared on Twitter are visible directly in users' Twitter feeds.[67] Due to an influx of inappropriate content, it is now rated 17+ in Apple's app store.[68]
2012
December 18
Userbase
Twitter announces it had surpassed 200 million monthly active users. Twitter hit 100 million monthly active users in September 2011.[69]
Twitter releases an 800-page prospectus in preparation for the IPO.[78]
2013
November 6–7
Financial/legal
On November 6, 70 million shares[79] are priced at US$26 and issued by lead underwriter Goldman Sachs.[80] On November 7, trading of the shares begins on the New York Stock Exchange. The share closes at US$44.90, giving the company a valuation of around US$31 billion.[81]
2014
April
Product
Desktop website layout majorly redesigned. This layout served as main front end for desktop web users until July 2019.
Twitter confirms acquisition of mobile ad retargeting startup TapCommerce.[83]
2014
July 31
Acquisition
Twitter acquires password security startup Mitro and open sources the product.[84]
2014
November 12
Product, userbase
Twitter announces "Instant Timeline"—a way to show users who have just created accounts interesting content even before they have followed anybody. Around the same time, Twitter announces that it will make the timeline more customized, highlighting to a user the most important tweets while they were away, rather than simply showing a reverse chronological feed. Other features announced include better video capability and the ability to share public tweets privately with one's followers to discuss them.[85]
2014
December 2
Product
Twitter announces a new suite of anti-harassment tools and promises faster response times for abuse complaints.[86]
2015
January 20
Acquisition
Twitter acquires India-based mobile marketing startup ZipDial.[87][88]
2015
January 21
Product
Twitter officially launches its "While You Were Away" feature.[89]
2015
January 27
Product
Launch of video uploading through mobile app and direct messaging in groups.[90]
2015
February 11
Acquisition
Twitter announces that it has acquired Niche, an ad network for social media stars, founded by Rob Fishman and Darren Lachtman.[91] The acquisition price is reportedly $50 million.[92]
2015
February 17
Product
Twitter lets people share team accounts without sharing passwords, with its new TweetDeck Team feature.[93][94][95]
2015
March 5
Product, monetization
Twitter announces that it will tap data from its Marketing Platform Partners and allow publishers to target ads to specific audiences based on that data.[96][97]
2015
March 9
Acquisition
Twitter acquires Periscope, a live video streaming startup.[98][99]
2015
March 23
Product
Twitter starts rolling out a "Quality Filter" to verified iOS users so that people can more easily keep bullying and unpleasant tweets out of their stream. A number of news articles commented that it worked quite well.[100][101][102][103]
2015
March 31
Product
Twitter publicly launches Curator, a real-time search and filtering feature for media outlets, that some commentators call a Storify competitor.[104][105][106]
2015
April 2
Acquisition
Twitter acquires TenXer, a platform for developers and engineers to collaborate more effectively.[107]
Twitter acquires with $532 million in stock TellApart, an ad technology company with rich user profiles, and partners with DoubleClick, Google's ad exchange.[109][110][111]
2015
April 28
Financial
Twitter shares fall in price by about 18% based on their disappointing quarterly revenue ($436 million), earning, and user growth numbers.[112][113][114] The drop begins even before Twitter's official announcement because the results are scraped by financial intelligence firm Selerity from Twitter's website.[115][116]
2015
May 18
Product
Twitter completes the rollout of its new search interface for logged-in web users.[117][118]
Dick Costolo steps down as CEO, co-founder Jack Dorsey returns as interim CEO. Costolo will remain on the Board. Shares are up 3% on the announcement.[122][123][124]
Twitter debuts Twitter Moments, a way for people to get a quick overview of important tweets or chains of tweets that occurred recently.[128][129]
2015
October 14
Company operation
Omid Kordestani leaves his job as Chief Business Officer at Google to become Executive Chairman at Twitter.[130] His base salary is $50,000 and he is eligible for up to $12 million in stock based on the company's performance.[131][132]
2015
November 3
Product
Twitter replaces the Favorite button with a Like button and the star symbol (used to symbolize favoriting) with a heart symbol.[133][134][135] Twitter reports a 6% increase in usage of the feature after the change,[136] and also appears to be experimenting with offering a more diverse set of emojis, prompting commentators to draw parallels with Facebook's Reactions feature.[137]
2015
November 4
Product
Twitter launches a political transparency page, so that people can better engage with policy issues on Twitter.[138]
2016
February–March
Product
Twitter rolls out a change to its feed, making recommended tweets the default option, rather than the reverse chronological format that it had used since launch.[139] The rollout officially begins on February 10.[140][141] The rollout is completed on March 17, 2016.[142] Users are allowed to opt out, but Twitter reports in April 2016 that the percentage of users who opted out is in the "low single digits".[143]
2016
May 24
Product
Twitter announces that attached photos and videos will not be counted towards the 140 character limitation, and that a tweet beginning with a handle will be seen by followers.[144]
Twitter acquires Magic Pony Technology, a company based out of London that has developed techniques of using neural networks (systems that essentially are designed to think like human brains) and machine learning to provide expanded data for images.[147]
2016
June 24
Product
Twitter launches tags to location feeds with Foursquare. People can see which tweets are from a specific place.[148]
2016
September 23
Acquisition (potential)
CNBC reports that Twitter is in talks with potential acquirers including Google and Salesforce.com.[149] On the same day, TechCrunch reports on the departure of two key Twitter team members.[150]
2016
October 21
Downtime
A distributed denial of service attack on DNS provider Dyn's servers in the United States East Coast causes DNS resolution problems for many websites include Twitter, Reddit, GitHub, Spotify, and others, mostly for users in the Americas.[151]
2016
October 27
Company operation
Twitter announces that it plans to cut 350 jobs (around 9% of its global workforce).[152]
2016
October 27
Vine
Vine announces that Twitter would be discontinuing the Vine mobile app. Vine says users of the service would be notified before any changes to the app or website are made. The company also states that the website and the app will be still available for users to view and download Vines; however, users will no longer be able to post.[153]
2016
November 1
Company operation
Rishi Jaitly, Twitter's head of India, announces his departure from the company.[154][155]
Twitter acquires Yes, Inc., the company that made several apps including Frenzy. All of Yes's apps would shut down. In the process of the acquisition, Keith Coleman, who had served as CEO of Yes, becomes a new vice president of product for Twitter.[157][158]
2016
December 20
Company operation
Adam Messinger, Twitter's chief technology officer, announces his departure from the company.[159] On the same day, Josh McFarland, a vice president of product, also announces his departure from Twitter.[160][161]
2017
January
Twitter announces that it would shut down the Twitter Dashboard.[162]
2017
January 12
Competition
The founders of App.net announce that the platform will shut down on March 14, 2017. App.net has been called "an ad-free, subscription-based, Twitter clone".[163][164] The source code for App.net will be made available through its GitHub account.[165]
2017
January 18
Acquisition
Twitter announces it has sold Fabric, Twitter's developer platform, to Google.[166][167][168]
2017
January 20
Vine
Twitter launches an online archive of Vine videos.[169]
2017
January 26
Product
Twitter launches the "Explore" tab, which replaces the "Moments" tab. The Explore tab bundles together Moments, trends, live video streams, and search.[170]
Font size of tweets in timeline consistent; some tweets' font no longer appears larger.[178]
2017
June 15
Product
Redesign of user interface icons such as "like", "retweet", "reply", and circular profile pictures, following a trend widely adapted by other large social media sites.[179]
2017
November 7
Product
Twitter increases tweets' character limit from 140 to 280 for all accounts. The earliest rollout to select accounts happened in September.[180]
2017
November 10
Product
Twitter increases display names' character limit from 20 to 50 characters.[181]
2017
December
Product
Ability to post threads of multiple tweets at once[182]
2018
July 13
Product
Locked and suspended accounts no longer add to profiles' follower counts, making the appearance of a sudden drop in following on popular accounts.[183]
2018
September
Legal
Jack Dorsey testifies before the U.S. senate alongside Facebook COO Sheryl Sandberg.[180]
Earliest trial of vertical left-side navigation bar column on the progressive web app ("Twitter Web App"). Gradually rolled out, starting with Microsoft Windows 10 users.[185][186] In June 2019, this layout was rolled out to all users of "Twitter Web App".[187]
2019
May 7
Product
Added ability to attach media (images or a video) to quote tweets[188]
2019
June
Company Operation
Twitter reveals data showing thousands of fake accounts linked to foreign governments like Iran and Russia.[180]
2019
July 15
Product
Progressive web app front end (known as "Twitter Web App", formerly "Twitter Lite") set to default for desktop website users.
2019
July 15
Product
TLS 1.0 and 1.1 support ended, placing Twitter among the earliest sites to do so.
Multimedia viewer overhaul for desktop users of "Twitter Web App", with the host tweet and its replies appearing in a scrollable and retractable side bar on the right, similarly to Facebook and Instagram. Gradually rolled out.[190]
2020
June 1
Product
Legacy (2014) web front end, also known as "Twitter Web Client", discontinued.
2020
August 11
Product
Ability to limit replies to individual tweets to followed or mentioned users.[191] First tested in May 2020.[192] Expanded to be adjustable after tweeting in July 2021.[193]
Trial with changed retweeting behaviour, where users are prompted to quote the tweet with a comment rather than a menu with a selection between both. A quoteless retweet would only be done if nothing was entered in the text box. The trial lasted for a month.[195]
2020
December 15 to 16
Product
Shutdown of "M2" mobile web front end which commenced as mobile front end in the early 2010s and later served as fallback to low-end devices/browsers, as well as browsers with JavaScript deactivated or unsupported.
2021
May
Product
Removal of the automated picture cropping algorithm used for previews in tweets and timelines.[196][197]
Contents of Whistleblower complaint to the United States Congress is published, alleging multiple violations of United States securities regulations, the Federal Trade Commission Act of 1914, and a 2011 enforceable consent decree reached with the Federal Trade Commission after several issues between 2007 and 2010.[200]
2022
October 27
Company operation
Elon Musk completed the acquisition of Twitter.[201]
2022
November 1-9
Product
Announcement of new version of Twitter Blue with verification system, costing $7.99 per month.[202] Launched 8 days later.[203]
2022
November 8
Product
Addition of "Official" label for government, company, and public figure accounts[204]
2022
November 18-19
Company operation
Elon Musk reinstates several previously banned accounts, including Donald Trump[205][206]
2022
December 10
Product
Relaunch of Twitter Blue with higher price on iOS[207]
2022
December 18
Product
Brief ban on posting links to other social media platforms, reverted a day later[208]
2022
December 19
Company operation
Elon Musk runs a poll asking if he should resign as Twitter's CEO.[209]
2022
December 19
Product
Launch of gold verified checkmarks and square profile pictures for brands as part of Twitter Blue for Business, as well as gray checkmarks for government accounts[210]
2022
December 23
Product
Addition of public view counter (or "impression counter") to individual tweets.[211]
2023
January 19
Product
Twitter bans third-party client apps, resulting in the discontinuation of apps like Twitterrific and Tweetbot.[212]
2023
February 17
Product
Twitter starts charging for SMS two-factor authentication, with the feature being limited to Twitter Blue subscribers effective March 20[213]
2023
March 23
Product
Announcement of discontinuation of legacy verified checkmarks as of April 1,[214] later delayed to April 20[215]