I use facebook, but do not EVER use FB authentication. I've been burned in the past, like I suspect most of your detractors have. By authenticating using FB, I'm not just signing up with a website and giving them my own details, but potentially giving up the details of friends, access to post information as myself, the ability to read my information, etc. I will authenticate using Google, Github, Twitter, and other services, just not FB, ever again. I've removed all "apps", no longer like corporate pages, never "connect" it to a website or application, etc. Even my friends who are not technologically literate refuse to do it.