The Internet Archive's Wayback Machine is now running on a Sun Modular Datacenter.
Here's an excerpt from the "Wayback Machine Comes to Life in New Home":
The Wayback Machine is a 150 billion page web archive with a front end to serve it through the archive.org website.
Today the new machine came to life, so if you using the service, you are using a 20' by 8' by 8' "machine" that sits in Santa Clara, courtesy of Sun Microcomputer. It serves about 500 queries per second from the approximately 4.5 Petabytes (4.5 million gigabytes) of archived web data. We think of the cluster of computers and the Modular Datacenter as a single machine because it acts like one and looks like one. If that is true, then it might be one of the largest current computers.
Read more about Sun and the Internet Archive at "The Internet in a Box."