Here are some examples for BigComputing:
* GoogleInc is operating the worlds largest commercial Linux cluster, 
*** http://www.google.com/press/highlights.html
* DeutscheBank is running the worlds largest LotusNotes/Domino installation
* MicroSoft wants to introduce HailStorm with authentication services for some 10 million internet users
*** http://www.top500.org/
* GlobalComputing is a special case of BigComputing : see LucaCardelli's 
*** ftp://ftp.digital.com/pub/DEC/SRC/publications/luca/GlobalComputation.pdf
* BeowulfCluster

However some attempts for BigComputing might not scale.
Might PeerToPeer be the best candidate for BigComputing?

Isn't PeerToPeer the thing with the most trouble scaling.