londrum - 1:05 pm on Aug 25, 2012 (gmt 0)
they must use chrome and toolbar data for some things.
what about page speed? google said ages ago that page speed could be used in a "tie-break" situation, to move one site ahead of another in the serps.
surely the only way they can get data on page speed is from chrome and the toolbar, because not every site has analytics installed