Twitter co-founder Jack Dorsey sent the first tweet five years ago on 21 March 2006. Five years on Twitter is one of the largest social networking websites with a massive user-base worldwide with hundreds of thousands new registrations be day.
Twitter users now send more than 140 million Tweets a day which adds up to a billion Tweets every 8 days— by comparison, it took 3 years, 2 months, and 1 day to reach the first billion Tweets. While it took about 18 months to sign up the first 500,000 accounts, we now see close to 500,000 accounts created every day. All of this momentum and growth often pales in comparison to a single compassionate Tweet by a caring person who wants to help someone in need. – Twitter blog