Adam Trachtenberg of eBay just said in the “PHP Lightning Talks” session that last quarter 52% of all all eBay item postings were done via the web services interfaces, versus manually. [Update: See Adam's clarification in the comments.]
Chrs DiBona’s and Mark Lucovsky’s talk on Google progress on open source/standards and the Google AJAX search APIs were both excellent. I’m definitely going to play with the latter on my private site.
Last year Gibson Guitars had a great display in the exhibit hall but, alas, they’re not here this year. Sigh.