I like Google’s approach on the World Cup soccer: you may have noticed the adsense link on the top that adds the right ‘worldcup soccer block’ to your ‘personalized Google page’ (click this link).
Something I noticed the other day when looking for something specific on Google: previously clicking the links in the search results brings you directly to the appropriate site. However, since a couple of weeks, these links first redirect to Google before going to the right site. If you generally copied and pasted links, you would have noticed this too.