Why do we value Facebook so highly?

Facebook shares opened at $42.05, up from IP estimation of $38. Photo: Press Association

Wearing what looked like his hallmark hoodie, surrounded by excited employees, Mark Zuckerberg remotely triggered the starting bell for the American stock exchange.

At the push of a button his unprecedented internet giant entered the stock market, the biggest ever flotation of such a company. The first ever firm to be valued above a hundred billion dollars on its debut, many staff and executives became million and billionaires at a stroke.

The 28 year old with 900 million followers, started his site from a college dormitory in 2004.

In the same year Google launched at a now modest looking $23bn. As he becomes the new sweetheart of the stock market, his empire is worth hundred times that of his old rival Myspace.

Facebook has 900 million users in 70 languages, but investors want return, so how can a site that's grown so big, get even bigger?

Facebook shares opened at $42.05, up from IP estimation of $38.

Prizes will only come if the challenge can be met. Breaking into China, making money from mobiles, and beating off new legal issues - with a class action on privacy issues starting today.

Already some analysts are cautioning that a launch this hot could burn investors fingers.

After all, Facebook has sold on the open market for 20 times its projected annual revenue. But this historic launch may say as much about us as it does about the site, how we have come to use and value the internet to a truly dizzying extent.

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