The unsubscribe trick has been around a while. All it does is confirm the address they spammed was used by a person and add it to a new spam list of confirmed addresses selling it for a higher amount.
The only way that current problems will be aleaviated is by institution an Email transmission tax. Some where around 5 cents an email would be a good start. This would cut down on the amount of internet and intranet email garbage and chain mails that float around. I for one would be happy to pay it to see this crap end. Just think of what a 100,000 list spam would cost a spammer to do. ISP tracking of email is not a hard or uncommon thing to impliment either.
This however does bring up issues of internet taxes and government regulation of the internet. Something that won't be discussed again until 2005.