David – there’s nothing specific to Google in Prism. It’s also confusing in a sense that they mention Adobe AIR and Silverlight in the blog post, because Prism isn’t really competition for them; Prism is saying HTML and JavaScript is an OK platform. You could certainly still use Silverlight or Flash on a web service packaged using Prism though.
Prism is basically the equivalent of a .spec file or debian/ for a web service. In other words, it’s a bit of goo code, not really very complex or platform-like. Now I did raise the idea of possibly elevating some privileges for services packaged using Prism, but it’s likely not to be useful unless IE does something similar, which I doubt Microsoft would be interested in.
But the real thrust of your post is is about non-open services, and I wish I had a good answer here. I can say that I’ve recently removed some Google stuff from the default configuration of the GNOME Online Desktop work. And Havoc is working on a better system for giving the desktop information about which services you use, so we can adjust more sanely rather than having a set of default services.
The fact is, the computing industry is clearly moving in this direction. Ignoring it or stopping work on integrating with different services gives us less control over the future, not more.