As for stopping spam, there's no real way to redesign the email service which would prevent it.
You could set it up like an instant messaging client where you have to add people to a list before they can send you emails, but that would prevent anyone you don't know from contacting you.
You could charge per email. That would get rid of some of the spam, but not all of it. Mainly it would get rid of all those annoying aol chain letter emails. But then people wouldn't email eachother as often and would look for a free way to communicate, on which spam would propogate instead.
The only real way to stop it is to detect it. An ISP could look at all incoming mail and see that one sender is sending the same email to a thousand of its customers and assume that's spam. But that could also be a mailing list. So that's not a good solution. They could try detecting certain keywords, but again you might have false positives.
Really what you need is something like Hotmail has where you click a button to tell it a message is spam, and then they can remove that email from everyone else's inbox if enough people say it's spam. But even that tends to trigger on mailing lists sometimes when people are just tired of receiving it and click the spam button instead of taking the time to unsubscribe properly.
You could set it up like an instant messaging client where you have to add people to a list before they can send you emails, but that would prevent anyone you don't know from contacting you.
You could charge per email. That would get rid of some of the spam, but not all of it. Mainly it would get rid of all those annoying aol chain letter emails. But then people wouldn't email eachother as often and would look for a free way to communicate, on which spam would propogate instead.
The only real way to stop it is to detect it. An ISP could look at all incoming mail and see that one sender is sending the same email to a thousand of its customers and assume that's spam. But that could also be a mailing list. So that's not a good solution. They could try detecting certain keywords, but again you might have false positives.
Really what you need is something like Hotmail has where you click a button to tell it a message is spam, and then they can remove that email from everyone else's inbox if enough people say it's spam. But even that tends to trigger on mailing lists sometimes when people are just tired of receiving it and click the spam button instead of taking the time to unsubscribe properly.