The problem here is that human beings, as a general rule, stink at assessing intangible risk, and even when it is demonstrated to us in no uncertain terms, we do little to rectify it. Free search engines that value your privacy exist. Why don’t people switch? Conditioning to Google and the expected search result quality, and sheer laziness (most likely some combination of the two). Why didn’t people flock from Facebook to Diaspora or other alternatives when Facebook screwed with privacy options? Laziness, convenience, and most likely, the presence of a perceived valuable network of connections.