why does your cargurus not list private sellers? I see many cars listed by owner when not using this site.

Car gurus is a business. It makes money through dealer subscriptions. If you subscribe as a dealer, they make the customers send more info when they inquire about cars. I think they use the review system as a bargaining chip when it comes to signing dealers up - dealers that don't want to sign up are given generic poor reviews by generic, faceless people. Positive reviews are also screened to keep reviews down and apply more pressure to subscribe. Also I think it manipulates the market in their favor seeing how most individuals that have a well optioned,low mileage car, with a great history will typically ask towards the top end of the market for that particular kind of car. If you haven't noticed yet, the best deals on this website are always a run of the mill base optioned cars with high miles, tacky colors, and/or a bad history...