The average Facebook click-through rate refers to the percentage of users who click on a specific link or advertisement on the social media platform, out of the total number of users who view it. This metric is used to measure the effectiveness of a Facebook campaign or post in driving traffic to a website or landing page. A higher click-through rate indicates that the content is engaging and relevant to the target audience, while a lower rate may suggest that the content needs to be improved or targeted to a different audience.