Twitter executives Dick Costolo (R), Evan Williams (2nd R), Biz Stone (C) and Jack Dorsey (2nd L) celebrate as Twitter IPO begins on the floor of the New York Stock Exchange in New York, November 7, 2013.[Photo/Agencies]

In San Fransico 

At Twitter's headquarters in San Francisco, offices opened early and hundreds of employees flocked to the 9th floor cafeteria to watch the festivities on TV while eating "cronuts," a croissant-donut hybrid, made by Twitter's resident chef, Lance Holton.

The IPO is the latest milestone for a service that was born out of a nearly-defunct startup in 2006 and was derided by many in its early years as a silly fad dominated by people talking about what they had for breakfast.

But Twitter quickly began to penetrate popular culture in unexpected ways, with its open design and broadcasting format attracting celebrities, athletes, politicians and anybody who wanted to share short, punchy thoughts with a digital audience.

Its business potential developed more slowly, and the company appeared to be floundering as recently as three years ago, when it was riven by management turmoil and frequently crippled by service outages.

Under Dick Costolo, who took over as CEO in October 2010, Twitter has rapidly ramped up its money-making engine by selling "promoted tweets," messages from marketers that are distributed to a wide-ranging but targeted group of users. In the third quarter, Twitter had $168 million in revenue, it said, more than double from a year prior.

The NYSE, which snatched the listing away from its tech-focused rival, Nasdaq, marked Twitter's debut with an enormous banner with the company's blue bird logo along its Broad Street facade.

British actor Patrick Stewart, of Star Trek fame, rang the opening bell at the Big Board together with nine-year-old Vivienne Harr, who started a charity to end childhood slavery using the microblogging site.

"I guess I represent the poster boy for Twitter," Stewart said, adding that he had only been tweeting for about a year.

Costolo and Twitter's three co-founders - Evan Williams, Biz Stone and Jack Dorsey - appeared on the packed exchange floor to witness the beginning of trade.

At current valuations, the stakes owned by Williams and Dorsey would be worth around $2.7 billion and $1.1 billion, respectively. Costolo, who invested $25,000 in the fledgling company in 2007, holds a 1.4 percent stake worth about $360 million.