I believe they "don't want to be evil" and try to respect privacy laws, but why launching a campaign for a product that is free and doesn't generate any revenue?
I've never seen Google advertising for Froogle, Youtube or any other of their free services.
Maybe the reason is to get rid of spam? Marshall over at Webmetricsguru could be right, when he writes:
"My feeling is that Google will need to incorporate people ranking URLs more directly and transparently than it has - ie: there's so much spam in top categories like travel and health...it's time for the search engine to actually show how many times a URL has been clicked on in the search results (say over the last month or year) as a way to know how popular it really is."
Should webmaster keep on using Google Analytics?