It would be relatively easy to make an OpenID server that only used an email ping as the authentication method. Your OpenID identity could be something like:

http://mailauth.example.com/evan@prodromou.name

…with no prior account at mailauth.example.com needed (unless you wanted to store some profile information there). This would centralize the email confirmation round-trip process, and make it easier for people with spam controls to whitelist just one confirmation server.

You could do just one email confirmation once per browser session (or even longer, at your option) — after that, you stay logged into mailauth.example.com. You wouldn’t have to confirm once for every site you log into.

This seems like it could be fun… I might try to hack it together.

As for the problem about people who aren’t always able to access their email, this problem occurs already as most sites require you to verify your email by clicking on a link or entering a code. If you aren’t bothered about verifying your users email (most sites shouldn’t be) then you can just setup the users session once the registration is complete so they only need to click the link if it expires.

Crosbie, all very good points. Explains why things are the way they are and will continue to be for some time.

Websites had to cater for people without them.

Even today, many people don’t have their e-mail accessible via the web, but only via a pop client on their home PC.

However, yes, for those people able to retrieve their e-mail at the time they register with a web site, e-mail based authentication is just as sufficient as a simple name/pwd pair.

But, are new sites yet able to dispense with name/pwd? Perhaps they can now offer some varieties:
1: Name/pwd - optional e-mail
2: E-mail/pwd - e-mail only occassionally accessible
3: E-mail - e-mail always accessible

Half the problem is keeping the registration process simple and familiar.

No password needed for this website :)

They are located in my hometown, The Hague, Holland.