I just checked my email, and received about 140 spams in two days. That is alot. Spam is annoying, but the filtration is worse, as i may miss something. I do have my own email server now, now to throw in a flexible IMAP server, and put Squirrelmail to use.
I was thinking about two ideas with spam. One is a challenge response. This helps in two aspects. One, it slows down sending time, and two, if the challenge is made more non-computer figureoutable, it should help, though lists would have to be approved.
Such as the challenge "how many letters are in this sentence?". A human would have to understand the question, at least for now, so a computer would not be able to respond to the challenge. The cons to this approach are many. For one, it is annoying for humans to do such work to make the response. Two, the questions would probably need to be rotated, making more work. Three, getting lists on everyone's white list would be quite a bit of work. Four, responding to large quantities of email (such as tech support) would make this untenable. Plus, the approach seems incorrect.The doesn't address the issue, it just adds barriers.
The other idea was pulling email, as opposed to the current pushing. Perhaps, instead of sending email, the sender only sends a token, mentioning where the email actually resides, then the receiver would have to pull the email. The advantages are many. The single point of failure as with a company's single email server is less important as it does not house the bodies. Spammers would have to have a real ip address that is availible for the entire time people are expected to read it (and if there was an incubation period a pre-screening crew could warn of the trash, similar to how usenet is better for downloads than ptp). Currently, POP3 and IMAP servers are completely open, and spam is dealt with afterwards. This way, they would be completely closed (unless whitelisted, which wouldn't be required except for very large lists). This would ultimately save on bandwith, and the non-read spam is never sent. The main con is that the sender can tell if and when the reader reads the email. Though, this can also be a pro, as if an email is mistakenly marked as spam, the sender can resend. I'd actually like that. It would remove the problem of deletion of valid emails when they were mistakenly deleted, for whatever the reason. Another con is the requirement for a place to send the email. But, i think enough ISPs have SMTP servers availbile.