On Wednesday, Facebook filed an S-1 document with the United States Securities and Exchange Commission announcing its intention to sell shares to the public. The eagerly anticipated move by the world's dominant social networking site sees Facebook's books open to potential investors - and the just plain curious - for the first time. Although the IPO will mean the internet giant will answer to shareholders and a board, the stock structure will see Facebook founder Mark Zuckerberg controlling 57 percent of voting shares.

While the IPO filing is big news in financial circles, Facebook's 845 million active monthly users (according to figures in the filing) won't have noticed any difference when logging into the site - yet. But there's no doubt that Facebook will now be under pressure to increase revenues to keep shareholders happy. Figures included in the filing show that while costs ballooned from US$942 million in 2010 to $1.995 billion in 2011, net income rose from $606 million to $1 billion in the same period.

The filing also reveals that Facebook makes relatively little on advertising on mobile devices, which are rapidly becoming a preferred platform for accessing not only Facebook, but the internet as a whole, for many users.

Just how Facebook will use the personal information of its millions of members and leverage its staggering reach to generate profits - and whether it can do so while staying true to Zuckerberg's stated mission of making "the world more open and connected" - will now come under the scrutiny of not only industry pundits, but shareholders.

While Facebook shares are already traded on a closed market, it will be publicly traded from sometime later this northern spring. The offering is expected to raise as much as $10 billion with the company expected to be valued at somewhere around $75 to $100 billion. Not bad for something that started life in Zuckerberg's dorm room less than a decade ago.