Google wants you to participate in an "identity system that follows you everywhere", so they can learn your behavior and preferences and show you relevant, timely ads. Facebook wants exactly the same thing, for exactly the same reason. Both services want you to stay logged in as long as possible. Both services offer authentication for 3rd-party sites to give you even more reasons to be logged in. The author sees a difference that I don't believe exists.

...said the person with the username "onemorepassword".