According to recently released figures from eMarketer, Facebook‘s revenue for advertising alone — which excludes revenue for virtual currencies and other sources — came to an astonishing $1.86 billion for all of last year. Not bad for a web startup that’s yet to see its seventh birthday.

As we reported last month, Facebook was on track to reach the $2 billion mark for revenue in 2010. When other revenue streams are counted along with ad revenue, it’s easy to imagine that the $2 billion revenue was achieved and possibly exceeded in the past year.

As users spend more and more on Facebook Credits, which got an extensive roll-out through online and brick-and-mortar retailers throughout 2010, the virtual currency is likely accounting for an increasing amount on Facebook’s balance sheets. After all, Facebook collects around 33 cents on the dollar for Credits spent within the Facebook ecosystem of apps and games — games that grow more popular with each iteration.

As for the ads, Facebook’s serving more than 50 billion display ads per month and was on track to serve 1 trillion display ads for the year.