iHack, therefore iBlog

XHTML has
that capability, as additional semantics can be trivially added by anyone simply
by using class names (a la microformats). However, those semantics are layered
on top of existing behaviors, so there’s always a “fallback” interpretation for
systems which don’t recognize the new
information.

In standard, schema-based
XML, the situation is very different. Extensibility is handled via namespaces
(themselves a controversial construct), and the only fallback behavior is to
ignore the data completely. Thus, if you’re worried about data interchange, you
need to either stick precisely to the standard, or duplicate analogues of your
new information inside old tags.
Ick!

This doesn’t even take into
account the fact that there’s zillions of people in the world who can write
HTML, or the fact that all HTML documents can be trivially rendered by browsers
on all kinds of different devices. All that’s missing is the social conventions
needed to help people realize they *can* do structured document editing in XHTML
— which is what microformats are all
about.

I think this is a sucker’s
bet…