Which microblogging service was created by Jack Dorsey, Noah Glass, Biz Stone, and Evan Williams? Twitter was.
Twitter grew out of Odeo, a podcasting company, in 2006. The original project was called Twttr, reflecting both the short-message concept and the five-character naming style associated with SMS services. Jack Dorsey developed the initial idea and prototype, while Noah Glass, Biz Stone, and Evan Williams helped shape the product and its company.
Dorsey posted the first public message, “just setting up my twttr,” in March 2006. The service was initially tested internally by Odeo employees before being introduced publicly on July 15, 2006. Its short posts made it a defining example of microblogging, especially as users adopted it for live commentary, breaking news, and public conversation.
The question refers to the service's historical name, Twitter. In 2023, the company and platform were rebranded as X, but that later branding does not change the canonical answer for a question about the service created by the four early founders. Threads, Mastodon, and Tumblr are separate platforms with different origins.