Twitter by the numbers at age five

Five years ago on March 21, Twitter co-founder Jack Dorsey fired off the first tweets officially giving life to the micro-messaging service:

Here are some facts about the San Francisco-based startup:

- Dorsey's Twitter account @jack automatically sent out the first tweet, "just setting up my twttr," on March 21, 2006 and Dorsey followed it up with the first "human-generated" tweet "inviting coworkers"

- Twitter has more than 200 million registered users sending more than 140 million tweets a day

- Last year, Twitter users sent 25 billion tweets and the company added more than 100 million new registered accounts.

It has averaged 460,000 new accounts per day over the past month.

- Pop star Lady Gaga (@ladygaga) has the most Twitter followers with 8.78 million followed by Justin Bieber (@justinbieber) with 8.13 million, Britney Spears (@britneyspears) with 7.12 million, Barack Obama (@barackobama) with 6.97 million and Kim Kardashian (@kimkardashian) with 6.73 million

- Actor Charlie Sheen (@charliesheen) was the fastest to one million followers, picking them up in just 24 hours

- The hashtag (#) feature on Twitter which groups tweets by subject debuted in August 2007, proposed by a user

- In October 2009, Google and Microsoft began integrating tweets into their search products

- Twitter has 400 employees and is adding workers almost weekly

- Twitter is based in San Francisco, with additional employees in New York, Chicago, Los Angeles and Washington

- Twitter was incorporated in April 2007; it was co-founded by Biz Stone, Evan Williams and Jack Dorsey - @biz, @ev and @jack

- The initial Twitter logo was created by Stone, a former graphic designer

- Twitter chief executive Dick Costolo is a former improvisational comedian