[dllthomas]

Not a new idea, and one I've been mildly enamored of at various points. At this point I'm somewhat ambivalent, but I think the standard responses are (depending on details of the plan):

        (X) Mailing lists and other legitimate email uses would be affected
        (X) Users of email will not put up with it

    Specifically, your plan fails to account for
        (X) Laws expressly prohibiting it
        (X) Lack of centrally controlling authority for email
        (X) Jurisdictional problems
        (X) Public reluctance to accept weird new forms of money
        (X) Extreme profitability of spam
        (X) Armies of worm riddled broadband-connected Windows boxes
        (X) Dishonesty on the part of spammers themselves
        

    and the following philosophical objections may also apply:
        (X) Sending email should be free
        (X) Killing them that way is not slow and painful enough

https://craphound.com/spamsolutions.txt

As mentioned, I don't know if I've really been convinced it can't work, though I'm also not convinced it would (or should, maybe?).

Certainly it doesn't work at all unless transaction costs can be negligible.