Peter Coffee, Search Engine as OS: It might seem odd to call a Web search engine an operating system, but look at the fundamentals. The OS is the software layer, preferably invisible during normal tasks, that hides the details of resources behind a uniform interface that makes those resources more useful.

Spot on. The role of an operating system is first and foremost to provide a convenient set of abstractions to applications developers. Just because the main challenge for the past several decades has been providing abstractions for the underlying hardware doesn’t mean it will always be that way.