Just came across an Apple developer connection article on how Apple’s Keynote presentation software stores all presentation data in an xml document:

At the heart of the Keynote presentation file is the presentation.apxl file, which specifies every detail of the presentation’s appearance and behavior—from the appearance of the master slide and each individual slide to the transitions used between slides and the state of the presentation when the customer first opens it.

The article goes on to talk about some of the nifty possibilities of integrating your databases and applications with Keynote. My own idea is that with a little (ok, maybe a lot) of hacking, you could provide a Keynote presentation feed for your weblog.

I love XML.