I would never pay for shopping advice from people who might be paid PR shills. What's to prevent a guy from GM from signing on to answer questions and advising

I would never pay for shopping advice from people who might be paid PR shills. What's to prevent a guy from GM from signing on to answer questions and advising every single one of your questioners to buy a Chevy truck? More importantly, if your site tells me to buy a Chevy truck, how do I know that I'm not a victim of product placement? At least when I read competing ads for game consoles I know the bias of everyone involved. And reading ads is free!