SAN FRANCISCO – Without making financial details public, Twitter filed with regulators this week for an IPO, a deal that would be the most keenly anticipated Silicon Valley debut since Facebook Inc's in 2012.
Keeping the wraps on the deal means investors for now gain little insight into a corporation that grew in seven years from a notoriously unreliable novelty into one of the world's most influential media, communications and advertising services.
Following is a list of some of the major questions surrounding Twitter and its coming-out party, plus the views of industry sources and experts:
How big is Twitter, really?
The seven-year-old micro-blogging platform has said it has more than 200 million regular users posting more than 400 million tweets a day. Private investors have valued the company, which has 2,000 employees, at more than $10 billion.
The company is flush with cash, having privately raised more than $1 billion over the years. Its backers include venture-capital firms such as Benchmark Capital and Union Square Ventures and wealthy individuals including Russian billionaire Yuri Milner and Saudi Prince Alwaleed bin Talal, among others.
And how fast is it growing?
Twitter has grown swiftly since its creator Jack Dorsey sent out the first-ever tweet in March 2006. The company, which did not have a concrete business model in its early days, is now expected to rake in $1 billion in global ad revenue in 2014, according to advertising research-firm eMarketer.
The real-time information service, which is available in more than 20 languages, has acquired scores of companies over the years to improve its technology.
Notable buys include its $350 million purchase of online mobile-ad exchange MoPub this month and its acquisition of Bluefin Labs, a firm that tracks social media activity, in February for an undisclosed amount.
Is it profitable?
Some investors have hinted that Twitter is profitable. Much of its growth is coming from a booming mobile business, analysts say. Over half of its global ad revenue of $583 million this year will come from mobile ad revenue, according to eMarketer.
About 83 percent of Twitter's 2013 ad revenue will be generated in the United States alone. The company is expected to earn $308 million this year from mobile advertising worldwide, eMarketer estimates, up 123.2 percent from $138 million in 2012.
So Twitter spans the globe. But how many of its users and tweets actually originate from outside North America?
The United States has the most number of Twitter users with over 140 million accounts, according to a July 2012 study by social media research firm Semiocast that looked at over half a billion Twitter profiles. But users in countries such as Brazil are growing at a faster clip than U.S. users, the study said.
Jakarta was the most active Twitter city in the world in terms of numbers of tweets, Semiocast said.
Twitter is banned in the world's most populous country China, where the country's own Twitter-like service, Sina Weibo, has some 500 million registered users.
Twitter is aggressively expanding its foreign sales operations and is expected to push non-U.S. revenue to $319 million in 2015 from less than $100 million this year, according to eMarketer.
Who's really calling the shots at Twitter?
Twitter was founded by developers Jack Dorsey, Noah Glass and Biz Stone along with entrepreneur Evan Williams.
Williams was the micro-blogging service's first CEO. In 2010, Dick Costolo, then the chief operating officer, succeeded Williams.
Costolo, who turned 50 this week and holds a B.S. degree in computer and communication sciences from the University of Michigan, was a former improvisational comedy performer in Chicago and worked as a management consultant for eight years.
Under his watch, Twitter evolved into a company with a thriving advertising business by introducing new services like "promoted" tweets, and ads for businesses.
Twitter's board includes venture capitalist Peter Fenton of Benchmark Capital, former News Corp executive Peter Chernin, who helped launch online video service Hulu, and co-founders Dorsey and Williams.
Why did Twitter choose to file confidentially?
Submitting documents under the 2012 Jumpstart Our Business Startups (JOBS) Act means it does not need to disclose financial details such as sales and profit immediately to the public, avoiding the intense scrutiny that a formal IPO filing by a high-profile company is sure to invite.
By filing confidentially for an IPO, Twitter avoids being restrained by the so-called quiet period that prevents companies from discussing themselves while in registration to go public.
What happens next?
Companies that file under that law do not have to reveal certain details, such as risk factors and capitalization, until 21 days before it opts to embark on an investor roadshow.
Wall Street investment bank Goldman Sachs is lead underwriter and the lead law firm is Wilson Sonsini Goodrich & Rosati. JPMorgan Chase & Co, Morgan Stanley and Bank of America Corp have also been added to Twitter's underwriting syndicate, sources told Reuters.
What's the smart money say about its IPO?
Investors say Twitter's market debut may revive sentiment and prompt fellow consumer-tech companies to tap equity markets.
Facebook's mismanagement of its 2012 debut and its subsequent share-price plunge dampened the consumer-dotcom IPO market. But the leading social network has clawed its way back to its $38 IPO price in July by proving to investors that it can grow mobile revenue, lifting investor sentiment for consumer Internet companies.
That Twitter is choosing now to go public could mostly reflect bullish investor sentiment toward U.S. stocks - the Nasdaq has gained nearly 25 percent this year - and potential pressure from backers sitting on huge paper gains rather than a fundamental need to raise capital, analysts say.
(Editing by Frank McGurty, Edwin Chan and Ken Wills)