Perhaps, but I think it would be entirely within Google's principles to show me employment ads if some combination of my gmail and search usage indicated I migh

Perhaps, but I think it would be entirely within Google's principles to show me employment ads if some combination of my gmail and search usage indicated I might be looking for a new job. Do the principles and policies you know of have some kind of ethics angle, or is it just about the (quite real) risk of bad PR that could harm the magic cookies driving the ad business?