NEW YORK (AP) -- The Pope. President Obama. Queen Elizabeth. Oprah. You.
When Twitter started seven years ago as an obscure medium for geeks, critics dismissed it as an exercise in narcissism. Some thought it would be as intriguing as watching a bunch of people gaze at their bellybuttons. But it quickly matured into a worldwide messaging service used by everyone from heads of state to revolutionaries to companies trying to hawk products.
Now Twitter is taking the next critical step in its evolution - selling stock to the public. It promises to be one of the most hyped and most scrutinized initial public offerings since Facebook's Wall Street debut in May 2012. To be successful, the company will need to become an advertising behemoth and prove that the same service that has already helped change the course of history can also make money.
Twitter quietly slipped out news of its plan to go public in a tweet on Thursday afternoon. By the next morning, nearly 14,000 of Twitter's 200 million users had retransmitted the message.
"Twitter epitomizes the revolution of social media. More than Facebook, more than YouTube," says Fordham University communications professor Paul Levinson, author of "New New Media." "It caters to the immediacy, the equality of all users."
And yet, Twitter really isn't that big. Only about 15 percent of Americans say they've ever used Twitter, according to an August poll by the Pew Internet and American Life Project. That's up from 9 percent in June 2010. At the time of Facebook's IPO, an AP-CNBC poll found that 56 percent of Americans said they had pages on Facebook. Some 17 percent said they used the site several times a day.
Twitter's 200 million global users represent about one-sixth of Facebook's 1.16 billion. If Facebook were a country, it would be the world's third-largest behind China and India. Twitter would clock in at No. 6, edging out Pakistan.
Even so, Twitter generates more news than Facebook. A big part of that is its public nature, Levinson says. With their messages of 140 characters or less, most people tweet openly, for better or for worse, allowing the world a glimpse at their thoughts. Facebook, in contrast, gives its users a plethora of controls to hide or show posts to as many or as few people as they'd like. That means many users share updates only with people they already know.
"You can rub elbows with famous people instantly," Levinson says. "You can `at' the president, `at' a movie star, the same as your boyfriend," he adds, referring to the symbol Twitterers use to send messages to one another. "That's what makes communication in the 21st century radically different from any time in the past. It wasn't until Twitter that the combination of speed and access to anyone became available for everyone."
Perhaps Twitter's biggest appeal is that it allows users to see news unfold in real time. People can follow and even communicate with newsmakers. And they can witness history. During 2011's Arab Spring protests, Twitter became an essential communication tool in Iran as the country's government cracked down on traditional media after a disputed presidential election. Tech-savvy Iranians took to Twitter to organize protests. As the events unfolded, they used the service to send messages and pictures to the outside world.
Today, a billion tweets are sent every two and a half days. To be fair, most tweets don't comprise the world's weightiest matters. They are ruminations about lunch, the weather and Justin Bieber -and sometimes they involve career-crashing missteps of the Anthony Weiner sort.
Like Facebook, Twitter reaps most of its revenue from advertising. Research firm eMarketer estimates that Twitter will generate $582.8 million in worldwide ad revenue this year, up from $288.3 million in 2012.
While companies are flocking to Twitter to woo consumers, not all of them are convinced of its usefulness. More than 60 percent of U.S. marketers are on Twitter according to Forrester Research analyst Nate Elliott, but he says they are not "fully satisfied with the results." Twitter, he says, still needs to improve the way it targets advertisements to users and it needs to find more types of ads to sell.
Still, by 2015, eMarketer expects Twitter's annual ad revenue to hit $1.33 billion.
Twitter might never have become the world's digital water cooler if Noah Glass and Evan Williams had convinced more people to tune into a podcasting service called Odeo started in 2005. Less than a year after its birth, it became apparent that Odeo was destined to be a dud. Not even its own employees were using it that much.
By early 2006, Glass and fellow Odeo programmer Jack Dorsey were given the go-ahead to work with co-worker Christopher "Biz" Stone on a service that would serve as a zookeeper for a menagerie of text messages typically sent over a phone. It was an offshoot of Dorsey's longtime fascination with the dispatch systems used by police cars, fire trucks, deliver trucks and taxis. Dorsey