Please tell me, is it possible to use Facebook's API to detect whether user1 likes the page of user2? I mean without any authorizations or keys (or even with...), just write a code that will automatically query the API and see if whether a certain like between two Facebook accounts exist? Also, if anybody knows whether such options also exist for Twitter, Instagram, Youtube, Tumblr, Pinterest? If anyone knows, please confirm. Any help is greatly appreciated, thank you very much!