Privacy and Google's "behavioural ads"

Web users are impatient and time is short. Google has always strived for relevance in the search results and ads that it serves in response to a search term. No-one complains when an individual website serves up relevant content when we visit - see youtube.com as a good example. Google's allowing users to see and edit their profiles.

So what's the problem with Google's new behavioural ads?

This is the web at its best - intelligently serving relevant content to users.