Facebook has raised $500 million in a new round of funding from Goldman Sachs and Russia's Digital Sky Technologies (DST), valuing the world's popular social networking site at $50 billion, according to yesterday report from Dealbook.

The new valuation makes Palo Alto, California-based Facebook worth more than companies like Yahoo, e-Bay and Time Warner, said the report.

Goldman Sachs, the global investment banking and securities firm has invested $450 million, while Moscow-based Internet-investment group, DST, majority owned by Russian billionaire Alisher Usmanov has invested a further $50 million in Facebook.

DST had acquired around $200 million worth of Facebook stock in May 2009 and followed it up by acquiring an additional stock worth $100 million in July, in a deal that valued the fast-growing s social networking site at $6.5 billion (See: Digital Sky's stock purchase values Facebook at $6.5 billion). 

As part of the deal, Dealbook, citing people involved in the discussions said that Goldman is expected to raise as much as $1.5 billion from investors for Facebook at the $50 billion valuation.

Started as a web service Thefacebook.com when founder and chief executive Mark Zuckerberg was a 19-year old sophomore at Harvard University in 2004, Facebook's phenomenal popularity has made Zuckerberg one of the world's youngest billionaires and his privately held company is projected to have 2010 revenues of $2 billion, according to Time.

Facebook, with over 500 million users, passed Google and Yahoo as the most visited site on the Web in the US in 2010, according to a new study from online measurement service Experian Hitwise. On Christmas Day, Facebook overtook Google as the most visited site in the UK.

As the social networking site grows bigger and bigger two questions industry experts are wondering about how much the company is really worth after all and when will Zuckerburg and his team decide to go public.

Industry insiders have been speculating for quite some time that Facebook will announce an initial public offering (IPO) soon. The speculation garnered strength after Facebook took the first step in November 2009 for an IPO in the future by setting up a dual-class stock structure to ensure voting control over the company by Zuckerberg and other existing investors.

The company created a dual-class stock structure and converted all of its current shares into Class B shares, which will have 10 votes each. It said the reason for doing it was, "Because existing shareholders wanted to maintain control over voting on certain issues" and "focus on the long-term."

Class A shares, which would be sold in an IPO, would carry one vote. Currently, Zuckerberg, Marc Andreessen, Jim Breyer, Don Graham and Peter Thiel are on the board of Facebook.

Although the company said that it has no plans to go public soon, analysts say that such dual-class stock structures are not unusual and indicate that the company is planning to go public.