Really glad you found it informative!

I think you could definitely white-label the DomainPolish idea and sell it to people hoping to build a Review X service. The problem is that if you just try to build a site yourself that lets you review anything it's very difficult to target your customers.

People search for "get feedback on my website" not "site to review anything". Picking a specific vertical makes marketing much easier. But it's a cool idea! I can put you in touch with the current owner of the DomainPolish source - he'd probably license it to you :)