Facebook CEO Mark Zuckerberg speaks during a news conference at Facebook headquarters in Palo Alto
Facebook hit 500 million users in 2010. The site has become a part of the cultural lexicon, and given us a new verb: "defriend" REUTERS

After being voted 'Person of the Year' by Time magazine Mark Zukerberg's brainchild Facebook is expected to post $2 billion in revenue for the year 2010.

Bloomberg cited sources close to the matter who said that the sales would double from 2009 revenue. The forecast beats earlier estimates that cited $1 billion in revenue for 2010.

Last year Facebook surpassed $500 million in annual revenue, Facebook board member Marc Andreessen told Reuters in July. Reuter had cited sources who claimed that Facebook had generated revenue to the tune of $700 million to $800 million in 2009.

Facebook's primary source of income is from advertisements and virtual currencies. According to Bloomberg, Facebook founded in 2004, will be the fastest company to reach the $2-billion mark compared to Google, founded in 1998, hit $1.5 billion in 2003 while Yahoo founded in 1994 posted $1.6 billion in revenues in 2003.

With around 550 million users in its fold, Facebook is sitting on a goldmine of information which can assist advertisers to plan targeted ads. Google's knowledge of users comes through running analytics on users' search characteristics while Facebook users reveal their preferences in their personal profiles.

WSJ had reported in May that Facebook hosts about 50 billion display ads per month. It had served 176.3 billion display ads in the initial three months of the year which accounted for 16.2 percent of the total ads, beating Yahoo and Microsoft who had served 131.6 billion and 60 billion ads respectively.

Through its virtual currency segment that is fueled by its Facebook Credits application, the company gains 30 percent of the revenue earned for goods sold through it. The application is used by gaming companies like Zynga.

However, Facebook is still at a nascent stage when it comes to monetizing its ad revenue potential. With other applications like Places that can still be leveraged for location-based ads, Facebook is sure to continue its march ahead.