The web is just another OS, with an enormous API and constantly-changing revisions of everything.
OSs are not even what most folks mean when they mention Windows etc. They mean the execution environment (runtime,libraries,shells). And the trend is to develop portable environments - JBOSS, .NET, whatever. We are at the beginning of the end of proprietary OS wars - OS will be no more important a decision than your editor or drive vendor, eventually.
