Let’s think for a moment about what we build, when we build things for the web. We build traditional web sites — still, I’d argue, the vast majority of the content of the web. These are document-centric, though they may — and indeed, increasingly do — include interactive, application-like content. We are also now frequently building more application-like, less document-like experiences. This, as we know, has been going on for quite some time but for most of that time, much of our application logic has resided on the server, with the client being a largely dumb interface.