[doesnt_know]

Your proposed solution isn't really email though. What you are describing has already been solved by instant messaging/jabber/twitter/facebook PM etc. Some of the solutions that already exist need a third part provider, others don't.

The problem to solve is how do you have a fixed address where anyone can contact you, spam doesn't get though and you don't have to maintain personal black/white lists. This is what email currently provides. Granted, the spam part varies depending on the provider.

[overbroad]

Yes, you defined the problem in the opening sentence of your second paragraph. But I disagree that you should not have to maintain a whitelist. What are your email contacts i.e. what is your email address book? You already maintain a list of people you correspond with, whether you think of it that way or not. And when you want to correspond with someone new, you have to give them your email address. As it stands, there is no _reliable_ way for them to look it up. There is no worldwide directory of email addresses. In fact, what do we do? We try to hide lists of email addresses.

If everyone had a fixed address with a mail server running, "lookup" i.e. simple MX lookup, might be possible, e.g. if your IP address is 1.2.3.4, anyone could send mail to inquiries@[1.2.3.4] or something like that. But I'm not sure that alone really solves the problem.

Email still works without a worldwide directory. People exchange email addresses and they keep lists of them known as address books.