Google is constructing a price index
Google is using its vast database of web shopping data to construct the ‘Google Price Index’ – a daily measure of inflation that could one day provide an alternative to official statistics.
Google has not yet decided whether it will publish its index, but "Mr Varian said that the GPI shows a “very clear deflationary trend” for web-traded goods in the US since Christmas."
The full article is here, including the story of Hal Varian's pepper grinder and for the pointer I thank Brent Depperschmidt.