> I mean, what 400,000 sites do you think Chase was advertising on? Ones that really have to do with banking? Or just ones that, by some idiotic metric, have a keyword that ".equals('banking')"?

The reason a Chase ad ends up on 400K sites is not because all of those sites are contextually relevant, it's because of retargeting. A user goes to chase.com, gets pixeled, and then shown retargeting ads on what ever websites they happen to visit that are hooked up to the exchanges. This could be either a good or bad thing.