[Rudism]

I don't imagine this would take off, especially once people realize they can't receive any automated emails anymore (sign up confirmations, email validation requests, e-bills, reciepts for online purchases, any kind of service notification, etc). It would require probably maintaining a second email for those kinds of things, and then you've got the same problem as before but now with a second (extremely limited) email on top of it to worry about as well.

Something a little less extreme such as a whitelisting system might work better (only people on my whitelist may email me... if you email me and you're not on my whitelist you have to fill out a captcha or something in a response before I ever see the email, and then I have the option of either whitelisting you, doing nothing, or adding you to a permanent blacklist). That would allow me to whitelist the addresses I really care about while cutting out all other unwanted content. Main problems I see with something like that would be that email becomes even more asynchronous and unreliable than it already is.

Best solution is to just tear it down and replace it across the board with something better like XMPP. (A man can dream.)

[jiggy2011]

The problem with that of course is that automated emails won't get through unless they can also solve your CAPTCHA or you have whitelisted them in advance which would either make usability worse (when you sign up for a service you have to remember to go and whitelist them) or your CAPTCHA has to easy enough for a bot to break which basically defeats the point.

[Rudism]

Agreed. You would have to pre-whitelist, or at least have a junk folder you could look in where non-captchad messages get stored for a certain amount of time before being purged so that you could fish out the emails from non-whitelisted addresses that you're actually expecting to get (and then presumably whitelist them from there for future emails).

[jiggy2011]

The problem with that is that you're actually going to look at email in your junk folder. Spammers would love this because they know that there's a chance that you'll actually see their crap even if it gets filtered.

The entire point of having a junk folder is you don't have to check it apart from the rare occasion you get a phone call saying "hey , I sent you an important email why haven't you replied?"