Prefpass offers a service that will ease your pain when it comes to registering on websites :

PrefPass is all about one thing: personalizing web sites without having to register. Specifically, we are on a mission to reduce 3 big annoyances that everyone has to deal with today:

Long registration forms
Needless passwords
Annoying spam

Prefpass is currently in private beta status which means you have to send them a request to receive an account, just as you did in the past to get an account for other private beta startups such as Vox.

So, how do we do it? Well, in the past, people tried heavy duty "digital ID" types of systems like Passport. The thing is, these kinds of systems are doing the wrong thing: they're trying to help you prove that you really are some specific person out there in the real world.

Prefpass has understood you can stay completely anonymous on the internet - but yet register on websites. The only information most websites require is proof you're the same guy with that emailadress as last time you visited so your preferences will be saved and kept private. And privacy is what it is all about on Web 2.0 !