I do like it, one question though, anyone can speculate as to why he says use an xmp tag, but then himself uses a textarea on the page? And will google index it?
Most users won't have to do this.
Google does index <xmp>, see e.g. the search result for "devo site:www.the-pope.com". The word "devo" is inside <xmp>.
I'd think it would take a long time to phase this tag out as it was apparently popular among HTML spec writers, which means there's probably a ton of them still in the wild:
<\/xmp>
inside the text?I would speculate (after no more than a cursory glance) that using the xmp tag is the Google-indexable method of writing your page? Google should see it as plain text on a web page.
Textarea support could be to provide interactive/editable pages?