Nice article. I would argue that JSON is suited for a structured web though. Imagine even something like RSS turned into a JSON structure — if everyone would simply publish open JSON feeds we could have a lot of interesting client-side applications...
I know a few people who've been working on a JSON Schema for the more formal datasets. I worked on an Internet Draft for this for a while, before the effort crumbled. Like most of the Web though, JSON really tends to shine when it is semi-structured — with any additional structure applied to it, post-hoc, by the consumer. CouchDB is a good example of a system that embraces this property.
