In violation of agreements, definitely, if you believe Facebook's public statement. I think it would be risky for Facebook to lie about their developer policies

In violation of agreements, definitely, if you believe Facebook's public statement. I think it would be risky for Facebook to lie about their developer policies but that doesn't mean it's impossible. I don't have time right now to dig through archive.org to find an old copy of those, unfortunately. For a much better examination of legal aspects than I can provide, see https://www.lawfareblog.com/cambridge-analytica-facebook-debacle-legal-primer https://www.lawfareblog.com/cambridge-analytica-facebook-deb.... Please keep in mind the sentence "I am leaving aside for now the potential claims under British and European law, but those add to this list considerably," which is rather important given the EU's more aggressive privacy regulations.