And instead of waiting for the user to obtain a client certificate, ISPs should just issue one when the user signs up.
Client certificates are no less secure than the consumer authentication methods used today.
I've solved all the problems of user registration, privacy, cookies and security. All you have to do is execute the plan. The server site reads this certificate and maps it to user-registration information. While server certificates are common because SSL insists upon them, client certificates have languished because they're optional. It's shameful how rarely we use client certificates, given that they're standard and browsers have supported them for years.