Most of the bloggers I read who were at WEB 2.0 have already blogged about JotSpot. I wasn't at WEB 2.0 but now it's my turn.
In short, I'm very excited about JotSpot which is a web development platform built on top of a wiki engine. As you may have guess already, I'm a big fan of wikis. I've also long been interested in placing real-time structured data in documents (it's one of the things that excited me about SGML in the first place).
I almost think of JotSpot as a team version of where I want to go with Leonardo. And whereas I'm focused largely on personal info hosting/publishing in Leonardo, JotSpot looks like it could be a great platform for building aggregators.
Beyond the information that's available at JotSpot you might want to check out Jon Udell's flash demo of JotSpot which made me feel like I was getting my own personal demo from JotSpot's co-founders.
I'd already been following Joe Kraus's blog, Bnoopy before JotSpot was announced. I hope he can find the time to get back to blogging more soon.
I just got in the beta program so I'll report more on JotSpot in the future.