Twitter

Twitter was a social network in the 21st century.

History
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 hit on Twitter. (BBCR: Submission)

In 2011, Patricia Menzies said that her phone could not access Twitter. (BFA: The Crimes of Thomas Brewster)