Document == Interface?

Ran across a link to Last Week in HTML5 and spent the rest of the day catching up with the drama surrounding HTML5. I sympathise deeply with Mr last week.

Giovanni Campagna has summed up something I've been thinking for a while:

Actually the web, is already divided in two big groups:

• Web of data
• Web of interaction

Web of data means all the page whose primary objective is to provide some information, either user-readable or machine-readable to the users, while web of interaction include web application, whose primary purpose is to provide additional services to the users. These two groups have very different requirements (GMail doesn't need RDFa in application code, while Wikipedia doesn't need a progress element), so specific markup languages may suit better the web site.

It's very strange to try to write application interfaces and documents in the same language. Too bad XHTML2 was strangled in infancy.