I agree that it&#x27;s a nice option to have and I doubt many companies care to only provide one method of communication via Facebook. But there will be some, as there have been in the past that wouldn&#x27;t let me register for their services since I didn&#x27;t have facebook (Spotify at one point, another was a productivity app that was featured on HN).<p>It just seems like a slow creep by FB to become (as cliched as this is nowadays) &#x27;too big to fail&#x27;.