Page and Brin themselves once pointed out the problems of accepting ads or paid placement, with some rather ironic examples: Furthermore, advertising income often provides an incentive to provide poor quality search results. For example, we noticed a major search engine would not return a large airline's homepage when the airline's name was given as a query. It so happened that the airline had placed an expensive ad,…
The main difference seems to be that today even getting the top organic search result doesn't provide enough clicks for advertisers, so they feel obliged to purchase ads for their own brand names even when they already rank first. It should be noted that this instance is simply a test and should not be taken as an indication of how these ads will be purchased. While I'm sure there will be numerous advertisers who fee…
It's not so much what you are going to see, as what you're not going to see. I'm sure BP is happy to buy a shiny image ad and take traffic away from wikipedias article on the deepwater horizon oil spill.