The great thing is that with one (X)HTML document, you can have a slide show, a printer-friendly version, and a screen presentation. I put markup and CSS examples right there in the document, ready to be printed, and simply hide them in the slide show. In some cases, I printed out the file for handouts, and then used the exact same file for the slide show. It was very, very handy. Eric's Archived Thoughts: Slide Show Beta
Eric Meyer is actually talking about a feature of Opera called Opera Show, but it describes what he has now accomplished in CSS, XHTML, and a little JavaScript: a browser-based slideshow that is just plain code underneath, with no plug-ins. It looks and feels like PowerPoint...except it isn't, and it can be used anywhere. Check out Eric's test file. Viewing source on that page shows a thing of beauty.
Dear Apple/Steve: please make Keynote export to this "format" automatically.
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