FullContact provides different social network links for your contacts via our Updates feature. A small number of these links may show up as broken. This can occur for a variety of reasons, such as a user deleting their account or the social network itself not providing a "static" link. For example, in the case of Facebook, a broken link likely means the user deleted their account, or they changed privacy settings so that you can no longer access it.
We are currently looking at ways to prevent broken links from showing up in web results. Thanks for your patience as we address this issue!