I don't know what the solution is. I also don't know anyone in the business who isn't trying to stem the spam tide at this point.

I am holding out some hope that the Anti Spam Research Group (ASRG) that has been formed by the IETF to look into the issue will make some progress. Still I think the problem is going to continue to get worse before it gets better.
Check out the ASRG charter...

The two technologies I see employed are based on blacklists/whitelists or scanning content or a combination of these two approaches. Neither mechanism is foolproof and everything I've seen to date requires a relatively high amount of administrative involvement to manually weed through what is getting blocked to make sure valid emails aren't being filtered.

This still doesn't do anything to deal with the fact that we're still forced to deal with the mail after it crosses the router and hits our wire. This means we're paying for the bandwidth that is being consumed by the spam. It sure would be nice to get some mechanism to block or prevent it upstream before it hits our link from the ISP.

Someone must actually be purchasing crap that is solicited in spam - if there was no money coming in, it wouldn't be so prevalent.

If anyone has any good solution (other than hunting down the spam-sending scum like the worthless filth that they are) please please please let me in on the secret.