Over four billion Web pages, each an average of 10KB, all fully indexed.
Up to 2,000 PCs in a cluster.
Over 30 clusters.
104 interface languages including Klingon and Tagalog.
One petabyte of data in a cluster -- so much that hard disk error rates of 10-15 begin to be a real issue.
Sustained transfer rates of 2Gbps in a cluster.
An expectation that two machines will fail every day in each of the larger clusters.
No complete system failure since February 2000.
It is one of the largest computing projects on the planet, arguably employing more computers than any other single, fully managed system (we're not counting distributed computing projects here), some 200 computer science PhDs, and 600 other computer scientists.