Is Facebook really worth $6.5 billion?

Facebook has been valued at $6.5 billion, after the social-network’s Russian backers agreed to pay $14.77 a share for Facebook common stock.

Russia’s Digital Sky Technologies wants to boost its stake in Facebook to 3.5%, and has announced its intention to buy £100 million worth of stock from Facebook employees.

With the company not yet listed on the stock market the deal could prove a windfall for employees of the five-year old site.

The $6.5 billion is considerably lower than the $15 billion price tag indicated by Microsoft’s investment back in 2007. However, in the court case against ConnectU – which claimed Facebook stole its idea – it was revealed the company’s internal valuation hovered around $3.7 billion, suggesting its founders won’t be too unhappy.

In a brief statement, the site’s co-founder Mark Zuckerberg claimed the deal was a positive move for the site: “This is recognition of Facebook’s growth and progress towards making the world more open and connected,” he says.

Facebook is expected to breach $500 million in sales this year, according to board member Mark Andreessen, representing a revenue increase of around 70%. However, nobody knows how much it costs to maintain the social-networking site.

Facebook recently surpassed 200 million users on its social network, up from 100 million users less than a year earlier, propelling it ahead of MySpace.