And hopefully not one owned by Facebook. Blogs with FB login commenting still have at least one "earn $$$$ working from home" comment and sometimes a flood of them.

I imagine that you can say that you don't trust Facebook, and then those reviews will be automatically excluded. Or perhaps that will automatically happen because all your friends don't trust Facebook.

Then you need to test who in your network has been compromised by fake reviews.

Its turtles all the way down.