Maybe the reason Facebook doesn't want to get into this space is because an ecosystem of trusted reviews would actually be a major problem for their customers (

Maybe the reason Facebook doesn't want to get into this space is because an ecosystem of trusted reviews would actually be a major problem for their customers (aka advertisers). It wouldn't be good for an ad platform to show an ad for something and then show the prospective customer the debunking of said ad. Facebook makes their money on the market being less efficient. If the market was super efficient and everyone bought what they wanted and was satisfied with it there would be a lot less need for advertising.