A look at the fully-packed racks inside a Facebook Data Center facility...

How many servers does Facebook have? For some time now, the stock answer has been “more than 10,000 servers,” a number the company began using in April 2008. Facebook has continued to use that number, even as it has soared past 300 million users & dramatically expanded its data center space.

Full story: http://www.datacenterknowledge.com/archives/2009/10/13/facebook-now-has-30000-servers/