[maggit]

I suspect you are reading too much into the word "identity". It is just a matter of identifying the endpoint, so the HTTP router can delegate requests from one user to the same backend instance in any given session. This, in turn, will give a user a consistent image of the state at the server independently of cache propagation in the backend. For example. You don't need the user's real life identity to do this, and you don't need the same identity across different sites or across different sessions.

This is currently sometimes done by cookies, which makes life difficult for HTTP routers. He is proposing a mechanism to keep the identifying-part while getting rid of problems in the HTTP router layer. The way I read this, it seemed to be without introducing additional privacy concerns and in fact removing some. (Cookies can carry more than identity)

There is a detailed technical discussion to be had about implementing all of this, and in this discussion any privacy concerns would become visible and open for discussion. But I think it is a leap to say that the comments in TFA would necessarily make for a world bereft of privacy ;)