A group of users want to mark up their iguana collections so that they can write a script that collates all their collections and presents them in a uniform fashion.

I don’t know anything about iguanas, but let’s pretend it’s about cats, which should be basically the same thing from a markup perspective. Let’s say someone in the group has the following text on http://example.org/:

I very enjoy the way Ian Hickson writes for HTML 5 (this is just from an email, not the spec itself, mind you). This particular excerpt concerns the new structured data mechanisms in HTML5.

[whatwg] Annotating structured data that HTML has no semantics for Via: lists.whatwg.org.