Update, August 9th 2009: It’s used only on Google Chrome, and it’s used by the Search Pad for improving the user experience by speeding up responsiveness. I’ve recently written a new post on the subject.
I’ve just used Yahoo! Search in Google Chrome. I got a typical Gears popup asking me if I want to let the web site use Gears. I still have no idea why Yahoo! suddenly likes using a Google product; neither Google Search nor Yahoo! Search are helpful for several keywords.
Yahoo!’s Search blog doesn’t mention it either.
Any info, anyone?