I like this idea, but I feel like it would be hard to make sense of in practice. Many things that people would think of as "plain web pages" might have to be classified as applications just because they have some AJAX components. That would satisfy some curmudgeons who don't like what JavaScript has done to the Web, but it would be confusing to the point of worthlessness for everyone else. The alternative is to be extremely liberal about what you classify as a "page," which seems like it would basically be the status quo.
That could be true but consider that on the desktop we have had “files” and “applications” for years without much of a problem. In fact, any time a document tried to do too much (ahem Adobe Reader) it turned into a bloated mess and we preferred simpler formats.
