Twitter, which Thursday revealed its plans to go public, came to life on March 21, 2006 when co-founder Jack Dorsey's account (@jack) automatically sent out the first tweet, which read: "just setting up my twttr."
Dorsey followed it up with the first "human-generated" tweet: "inviting coworkers." More than 170 billion tweets have since gone out worldwide. Twitter said on Thursday that it had 218 million active users, as of June.
Some facts about a global phenomenon:
- Justin Bieber (@justinbieber) has the most followers with 45,366,914 as of 2200 GMT Thursday, followed by Katy Perry (@katyperry) with 44,122,303 and Lady Gaga (@ladygaga) with 40,229,059.
- US President Barack Obama (@barackobama) is fourth with 37,501,850 followers; the announcement of his re-election victory in November 2012 was re-tweeted more than 800,000 times.
- The average Twitter user has 208 followers and spends 170 minutes on the site every month.
- There are more than 200 million active Twitter users. Eighty percent of all users access Twitter on mobile devices.
- About 20 million Twitter accounts are believed to be fake.
- The hashtag (#) feature on Twitter which groups tweets by subject debuted in August 2007, having been proposed by a user.
- In October 2009, Google and Microsoft began integrating tweets into their search products.
- In January 2013, Twitter introduced Vine, which enabled users to make and tweet six-second looping videos. Some 12 million Vine videos are uploaded every day.
- Twitter is based in San Francisco, with additional employees in New York, Chicago, Los Angeles and Washington. Its total payroll exceeds 900.
- Prior to Thursday's IPO announcement, many analysts valued Twitter at around $10 billion. By comparison, Facebook went public valued at $16 billion.
- Twitter was incorporated in April 2007, the month after it stole the show at the influential South by Southwest technology and indie music festival in Austin, Texas.
- It was co-founded by Biz Stone, Evan Williams and Jack Dorsey—@biz, @ev and @jack.
- Asked by AFP in March 2011 why Twitter is such a hit, Stone replied: "A big part is that it is just very simple and connects people to other people they would not otherwise be connected to."
- The initial Twitter logo was created by Stone, a former graphic designer.
- Twitter chief executive Dick Costolo is a former improvisational comedian.
A brief history of Twitter - in Tweets
Billions of messages are fired off weekly at Twitter, with some of them capturing defining moments in history or in the evolution of the San Francisco-based firm.
Below a sampling of ten memorable tweets since the Twitter era began.
"just setting up my twttr"
Twitter co-founder Jack Dorsey sent the first tweet, an automated message saying "just setting up my twttr." That same day he sent the first live tweet, "inviting coworkers."
US university student James Buck got off a one-word tweet after being taken into custody by Egyptian authorities at an anti-government protest in that country. In what is seen as an early demonstration of the power of Twitter to rally people to a cause, resulting outcry caused Buck to quickly regain his liberty. He proclaimed his release in a tweet reading "Free."
'There's a plane in the Hudson. I'm on the ferry going to pick up the people. Crazy."
A US Airways jet crash-landed on the Hudson River in New York. This tweet and others by witnesses and passengers was accompanied by a link to a picture of the scene, breaking the news well ahead of mainstream media outlets.
"HI TWITTERS . THANK YOU FOR A WARM WELCOME. FEELING REALLY 21st CENTURY"
Talk show queen and media royalty Oprah Winfrey took Twitter mainstream with her debut post and now has more than 21 million followers. She follows 149 people, according to her Twitter profile.
"From orbit: Launch was awesome!! I am feeling great, working hard, & enjoying the magnificent views, the adventure of a lifetime has begun!"
Astronaut Mike Massimino makes history with the first tweet from space.
Not a specific tweet, but an unofficial named given to a bold movement by thousands of Iranians who took to the streets to protest what they saw as a rigged presidential election and used Twitter to thwart government efforts to block them from communicating with one another and the world. Two years later, Twitter would become a vital tool used in "Arab Spring" uprising in an array of countries in the Middle East.
"Helicopter hovering above Abbottabad at 1AM (is a rare event)."
IT consultant Sohaib Athar unknowingly tweeted about US Navy Seals raiding a nearby home in Pakistan where Osama bin Laden was hiding out. Bin Laden was killed during the operation.
"Four more years"
US President Obama put out word of his election victory along with a picture of him and his wife, Michelle, hugging. The post was "retweeted" more than 800,000 times, becoming the most shared Twitter message to date.
"Dear friends, I am pleased to get in touch with you through Twitter. Thank you for your generous response. I bless all of you from my heart."
Pope Benedict XVI launched the first papal Twitter account, which had more than three million followers as of Thursday. The pontiff has a separate Twitter account in Spanish.
"Power Out? No Problem. You can still dunk in the dark."
A tweet fired off by the makers of Oreo cookies when a power outage interrupted the American football spectacle known as the Super Bowl was an instant hit, demonstrating the potential of Twitter to adapt cleverly to the real-time messaging platform.
"Breaking: Two Explosions in the White House and Barack Obama is injured."
Hackers from a group calling itself the Syrian Electronic Army commandeered a news wire account and posted this bogus message, showing that Twitter has become such a trusted place for the latest information that it had become a target.
Explore further: Lady Gaga first to reach 10 million followers on Twitter