[depoll]

We will eventually have some premium services that developers can get access to that will help them engage with their users or administer their services.

As for "Anonymous" login, that's Facebook's term for the service they promised (and we don't use it in our own description of the product for exactly the reasons you mentioned). We act as brokers between apps and users for their data, which includes an identifier that can be used for login. When an app chooses not to ask for personal data, we let the user know that we won't be sharing any of their information with the application.