I rely heavily on Google AppEngine which is a platform-as-a-service (PaaS) offering that I can deploy my apps on without having to worry about the actual server instances powering the application. Contrast this to infrastructure-as-a-service (IaaS) where I decide on the number of servers to spin up for my application. The benefit of a PaaS offering is an abstraction of the underlying server stuff (and all the nitty gritty server admin issues).