Facebook Anonymous Login is a menace to the open internet.<p>As a website operator, these are no longer <i>your</i> users, they&#x27;re Facebook&#x27;s users, and Facebook can take them away from you at any time.<p>As a user, these are no longer <i>your</i> website accounts, they&#x27;re Facebook&#x27;s website accounts, and Facebook can take them away from you at any time.<p>Putting Facebook in complete control of identity is not healthy for anyone. At least when you get email addresses from Facebook, you can bootstrap an independent relationship with your customers if necessary. From the user&#x27;s perspective: If Facebook blocks your account, the website operator can still validate your ownership with the email address.