Facebook seems to be taking another step toward Google’s AdWords. They will be determining the relevance of your ad based on feedback from those that view it. The highest possible score is a 10, and you get there by having people interact with your ad and not hiding or reporting your ad. The higher your score, the more exposure your ad will receive, and the less you will pay.
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Introducing Quality Score for Facebook: FB’s Ad Relevance Score Determines Ad Cost & Placement