Sure, renting computer power has long been an option, but the new players are making it much cheaper and easier:
Amazon charges 15 cents for a gigabyte of storage and 10 cents an hour for a server, services that customers say are up to 90% cheaper than rental alternatives from computer-hosting companies like Equinix and Rackspace.
The prices are low because these companies already operate huge networks of computers -- they're just looking to wring some extra cash out of their existing investment. (Hmmm, seems like an obvious business for Google, doesn't it.) In addition to the bargain prices, smaller companies also like rentals because they don't have to spend time and effort managing their own hardware and networks.
SaaS (Software as a Service) is old news. Let's call this trend HaaS (Hardware as a Service)!