You have it backwards. The more a publisher knows about it's users the more targeted ads they can sell for higher rates. Compare CPM on myspace.com (pennies) vs the wsj.com (tens of dollars). Yahoo and Google have similar people searching, but Google has been able to provide more personalized ads and therefore make more money. Advertisers measure their return for every dollar spent. If Google doesn't keep on doing a better job than other sites at personalizing pages their users will go elsewhere where they can find what they need more quickly.
Yes, knowing more about people's interests is great for targeted advertising.
However, providing (unpaid) personalized search and news can hurt you since there is less need for paid advertising.
If personalization is done really well, then it could have a very bad effect on paid advertising.
After all, if potential customers are likely to see your product via personalization, why bother to pay for paid advertising at all?