In the years since I signed up with my ISP, they've changed their main domain name several times. So now I get email under the name raydaly@xxxx.com and raydaly@yyyy.com and raydaly@zzzz.net. I've only used the xxxx.com address myself. So any email to the other accounts I know is spam (several hundred per day).

The easy solution requires a small amount of background. Most bulk email is usually batched to an ISP. So hundreds of email address could be in the message sent to one email server. So the same email that goes to any unused accounts contains spam for many other people.

Easy solution. Why don't ISPs look for an email sent to a "never used account" and then just stuff that email into a delete box before it gets sent into peoples' inbox. Certainly every ISP has these spam only addresses and could implement this.

Is this too simple to be a solution? Maybe. Or maybe spammer have figured a way around it. But I think it would work to cut an awful lot of spam. Something has to work soon.