Facebook invited a team from Intel's server group to take an inside look at Facebook's first built-from-scratch data center. (Facebook had previously leased space from others.) For 18 months, Intel engineers worked with Facebook to design super-efficient custom server board designs for the new facility.
Intel Free Press story: A Peek Inside Facebook's Oregon Data Center. Tens of thousands of energy-efficient servers handle the deluge of data generated by more than 800 million users.