For example, for VC in Runet there are a number of sites, allowing you to search likes and user activity, look for team members at the intersection and the Union of the sets of the subscribers look for the groups themselves on the subject, etc. - that is parsing internal search or the API of the social network. For example, vk.barkov.net, 220vk and other "spies", "scanners", "lakemary" and others, including application in VC.
Actually, the question is: is there the same thing but for Facebook? Not necessarily in Runet. Search by Yandex and Google gave nothing.