So which got more efficiency here,google knew what you want but while browsing anonymous browsers we may have to spend more time for finding the same,I am not encourage their spying behaviour on every user but at least it won't be a problem for most people.
As long as they function within the ambits of the privacy policy, it wouldn't be a problem. User information can be used for analytics purposes and also to track user behavior. But left unchecked this websites and social medias can use such information to adverse effect. The information is our of youe hands, and a leak, or deliberate breach could lead to the spread of such data among the wrong hands.
I would much rather safety than efficiency.