Uhm, no? I added the Facebook login option* to Stack Overflow, and I can assure you we don't really care which credential you use. We don't do anything differ

Uhm, no? I added the Facebook login option* to Stack Overflow, and I can assure you we don't really care which credential you use. We don't do anything different based on Facebook/non-Facebook creds. Go look at your app settings and you'll see that the Stack Exchange/Stack Overflow app only accesses your Facebook account when you login. We don't do any subsequent queries, by design (we actually discard the auth token, but that's harder to prove). The vast vast majority of the accounts on Stack Overflow use Google as a login provider. This has basically always been the case (http://meta.stackoverflow.com/q/31021/130213 http://meta.stackoverflow.com/q/31021/130213). * We waited until they supported OAuth 2.0, as we weren't comfortable with the older Facebook Connect.