The real issue imho is that there is no shared sales information. So you advertise BMWs to people who may have already purchased a car. I think that is a bigger issue.
This happened to me both times I've purchased a Jeep. I did a bunch of research on models and packages, price shopped a few dealers in my area, and then purchased a vehicle all over the course of a Saturday. For the next 3 months I get jeep ads following me all around the internet. I wonder how much revenue those completely irrelevant ads generated for google.
