Effective spam filters

I’ve said before that e-mail is broken. The way to fix that is to get a really good way to filter out the spam that doesn’t generate false positives or delay important e-mails by several days.

I’m sure this idea isn’t as revolutionary as I think it is, but wouldn’t checking for the validity of an e-mail address be a big step in the right direction?

I just went through and tried to reply to about thirty spam e-mails, and every single one of them bounced. It looks like (surprise) nobody spams from a valid e-mail address.

This isn’t the Earthlink “prove you’re human” approach - it simply checks to see if you’re sending from a valid address. I know there are programs that can do that. If you are, chances are pretty good it’s not spam.

Where can I get one of those?