The Instant Page feature sounds interesting. Has Google released any findings on bandwidth usage during typical browsing scenarios with this feature? How severe is this going to be for users with restrictive data plans?

I don't see an obvious way to turn this feature off. There is an option to uncheck "Predict network actions to improve page load performance" but this says it is only doing dns lookups and then navigating based on IP address.

I'm also curious how this will affect analytics. As a website owner, I now have to use their PageViews API to accurately track my hits from Google? Can websites opt-out of this service?