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).
This is great for the developer because the weight of the server admin hat that you have to wear is made a lot more manageable. The tradeoff for this abstraction is the lock-in that you have to endure as a developer.