Twitter was a social networking website on the Internet in the 21st century.
References
In 2008, after hacking his way onto a videoconference with Earth's scientific elite, the Eleventh Doctor urged them to disseminate his computer virus via every electronic means available, including Twitter, to contact the Atraxi. (TV: The Eleventh Hour)
In 2009, after the Torchwood Three team accidentally drove off the Severn Bridge, they heard a mysterious voice under the water. Back at the Hub, Ianto Jones stated that it was a hit on Twitter. (AUDIO: Submission)
In 2011, a news reporter stated that "Miracle Day" had been "trending". (TV: The New World) Oswald Danes, following his first television appearance during Miracle Day, trended on Twitter as well, the hashtag saying #forgive. (TV: Rendition)
In the same year, Patricia Menzies said that her phone could not access Twitter. (AUDIO: The Crimes of Thomas Brewster)
When the Doctor's TARDIS arrived on Apalapucia and Amy Pond asked for her mobile phone, the Eleventh Doctor assumed she wanted it to update her Twitter, rather than to take pictures of the sights. (TV: The Girl Who Waited)
At one time during an incident on Earth when certain women worldwide were being driven to unprecedented irrational heights, the number one trending Twitter hashtag was #realfemmefatales. (PROSE: Exodus Code)
After a wave of Shakri cubes arrived on Earth, this new phenomenon received a thousand separate Twitter accounts within the first three hours of their arrival. Upon learning this, the Eleventh Doctor exclaimed "Twitter!" in an irritated tone. (TV: The Power of Three)
Clara Oswald joked that "human souls trapped like flies in the World Wide Web, stuck forever, crying out for help" sounded like Twitter. This joke allowed the Eleventh Doctor to pick up on the knowledge she had acquired while she was partially uploaded, as beforehand she knew nothing about computers. (TV: The Bells of Saint John)
Clara later asked her class at Coal Hill School to use their mobile phones to spread the word on Twitter when she noticed that a plane outside her window had stopped moving, using the hashtag #ThePlanesHaveStopped. (TV: The Magician's Apprentice)
Behind the Scenes
In a non-canonical promo for The Day of the Doctor where the fourth wall is broken, Dan Starkey in character as Strax makes an important announcement on behalf of the Sontaran Empire for the apparently preoccupied audience: "Stop tweeting and watch the movie, you pitiful human scum!" This annoyed remark was followed by a comedically timed mood swing from fury to a wry grin at the viewers.
