Twitter laid bare its financial numbers for the first time on Thursday ahead of its initial public offering, one of the year's most highly anticipated events on Wall Street.

The company, which spun out of a nearly failed San Francisco startup in 2006, went through early years of management turmoil and unprofitability. But since 2010, Chief Executive Dick Costolo has firmed up the executive ranks and gradually dialed up Twitter's revenue engine.

Here are some key people from the boardroom, the sales force and the engineering corps who keep Twitter humming.

1. Dick Costolo, chief executive

A wry and driven entrepreneur who sold an online news distribution company to Google, Costolo was an early investor in Twitter before then-Twitter CEO Evan Williams asked him to join the company as chief operating officer in late 2009. Costolo wrote a tongue-in-cheek tweet: "First full day as Twitter COO tomorrow. Task #1: undermine CEO, consolidate power." He would become CEO one year later.

2. Jack Dorsey, co-founder and chairman

Widely credited as the man who invented Twitter as it is known, Dorsey served as Twitter's first CEO until he was pushed out by the board in 2008; he remained chairman. In 2012, Costolo asked Dorsey to return to the company to play an active role in plotting its consumer-facing product strategy.

3. Adam Bain, president of revenue

Costolo made his most important hire in late 2010, when he hired Bain away from News Corp, where he oversaw revenue products and sales at Internet properties like MySpace. Twitter's money man has since built Twitter's sales force around the world and oversaw the hiring of a significant part of its 2,000 employees.

4. Ali Rowghani, chief operating officer

Along with Bain, Rowghani is one of Costolo's most powerful deputies. A former high-ranking Pixar executive who shuns the spotlight, Rowghani is an influential voice on issues ranging from Twitter's mergers and acquisitions to choosing which outside investors are allowed to hold Twitter shares. He served as chief financial officer until late 2012, when he was replaced by Zynga alumnus Mike Gupta.

5. Peter Fenton, investor and director

In early 2009, Fenton's venture capital firm Benchmark Capital invested more than $21 million in Twitter for what is now rumored to be the largest institutionally held stake in the company. Fenton served a steadying presence on the board during the company's most troubled years.

6. Katie Stanton, head of international strategy

A former Google executive and State Department staffer, Stanton is responsible for expanding Twitter's operations in foreign countries, a potential challenge given that Twitter has vowed to legally fight against government censorship. Roughly 70 percent of Twitter's accounts are based outside the United States. Analysts have said the company will need to extract more revenue globally to sustain growth, a responsibility that partially falls to Stanton.

7. Chloe Sladden, head of media

Sladden joined Twitter in 2009 to win over media rivals, namely television producers and networks, who could be partners rather than rivals to Twitter. The ubiquitous "hashtag" seen on TV programs and ads today is partly the work of Sladden, the Stanford-educated former Current TV executive and management consultant.

(Reporting by Gerry Shih)