
Key Twitter moments: The first tweet —
In the early going, founders were using the vowel-free "Twttr" because they were focused on mobile and hoped to get the SMS shortcode 89887 (TWTTR). Unfortunately, according to co-founder Jack Dorsey, that was already owned by Teen People. This was his first tweet.

South by Southwest —
Twitter was still a digital infant in March 2007, when the world's technorati descended on Austin, Texas, for the South by Southwest Interactive festival. According to its founders, Twitter traffic more than tripled that week. All those influencers went home and shared the glories of a service even some tech-savvy folks didn't quite understand at the time.

'Arrested,' then freed —
With one word, U.S. graduate student James Buck set in motion the process that would eventually get him freed from prison in Egypt. He was arrested April 10, 2008, while reporting on protests in the city of Mahalla. His one-word tweet spread quickly to friends and new supporters, who shined a spotlight on his situation.

Miracle on the Hudson —
Dorsey calls January 15, 2009, the day Capt. Chesley B. "Sully" Sullenberger landed a failing U.S. Airways airliner on the Hudson River, a major turning point for Twitter. "It just changed everything," he said. "Suddenly the world turned its attention (to us), because we (Twitter users) were the source of news."