Data store: Facebook’s data center in Prineville, Oregon, is one of several that will help the company cope with its always growing user base. Facebook
The Biggest Cost of Facebook's Growth -- Technology Review
Running the world's largest social network will be a technical and financial challenge as it grows.
Facebook is the gateway to the Internet for a growing number of people. They message rather than e-mail; discover news and music through friends, rather than through conventional news or search sites; and use their Facebook ID to access outside websites and applications.
As the keeper of so many people's social graph, Facebook is in an incredibly powerful position—one reason its IPO this week is expected to be the largest ever for an Internet company.
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My Comment: Those data centers are not cheap.