Your post advocates a
( X ) technical ( X ) market-based
approach to fighting spam. Your idea will not work. Here is why it won't work. (One or more of the following may apply to your particular idea, and it may have other flaws which used to vary from state to state before a bad federal law was passed.)
( X ) Mailing lists and other legitimate email uses would be affected
( X ) Requires immediate total cooperation from everybody at once
Specifically, your plan fails to account for
( X ) Lack of centrally controlling authority for email
( X ) Public reluctance to accept weird new forms of money
and the following philosophical objections may also apply:
( X ) Ideas similar to yours are easy to come up with, yet none have ever been shown practical
( X ) Sending email should be free
Furthermore, this is what I think about you:
( X ) Sorry dude, but I don't think it would work.
Technology is constantly advancing in ways that are related to the problem domain in non-obvious ways, so repeating that old saw puts us in a reverse boiling frog situation. We never jump in the pot because it doesn't seem hot enough. Well, until someone ignores people saying things like this and does it anyway.
> Mailing lists and other legitimate email uses would be affected Allowing people to "opt in" to emails from people and companies they support could help, but you're right that this becomes a "spam tax". Which I'm mostly ok with, despite working for a company that sends a LOT of email.
> Mailing lists and other legitimate email uses would be affected
The receiving server could require proof-of-work for the first message from a sender to a given receiver, but not for subsequent messages. If spammers try to abuse this, it's easy for the user to click "block this sender"; if the spammer changes their sending address, they have to do a new proof-of-work.
> Requires immediate total cooperation from everybody at once
It could be introduced gradually: if a proof-of-work is provided, then the message is allowed to skip the spam filter. Small mailserver operators often have trouble with their messages being caught in spam filters by GMail and other large webmail providers; even if GMail alone started accepting proof-of-work, that would probably be enough to convince a lot of senders to start generating proofs-of-work, which would drive adoption.
> Lack of centrally controlling authority for email
This is no more difficult than any other backwards-compatible extension to an existing Internet standard.
> Public reluctance to accept weird new forms of money
OP's post didn't mention a weird new form of money. The original HashCash proof-of-work proposal included a weird new form of money, but it's easy to imagine a proof-of-work system that doesn't.
> Sending email should be free
Suppose the proof-of-work cost is calibrated such that it costs about $0.001 per email. That would be enough to destroy spammers' margins, but the vast majority of legitimate users wouldn't mind paying that.
> Ideas similar to yours are easy to come up with, yet none have ever been shown practical
I kinda see the point here... But I'd like to understand _why_ it isn't practical, because none of the arguments make sense to me.
at this point mailing lists are dead
> It could be introduced gradually: if a proof-of-work is provided, then the message is allowed to skip the spam filter.
Yes, because that totally will not harm the small senders (often individuals) whose newsletters can easily reach thousands / tens of thousands.
> Sending email should be free
> Suppose the proof-of-work cost is calibrated such that it costs about $0.001 per email. That would be enough to destroy
all mailing lists, yes. Look at open source mailing lists.
Or, to put it a different way: $0.001 is very roughly equivalent to a few minutes of CPU time. So if you have a single-core server dedicated to running your mailing list, you can onboard several hundred new subscribers every day.
Remember, the sender only needs to pay the proof-of-work when someone first joins the mailing list and receives the initial message. So, I don't see how this will kill mailing lists at all.
Firstly, the financial burden should be on the owner of the SMTP server / domain, rather than on the users themselves. Of course, the owner would pass the costs onto their users, but the system doesn't have to require an ongoing fee, just a bond for good behaviour. (This could be done with cryptocurrency, a smart contract, and a "proof of burn" type of transaction).
Secondly, and perhaps most importantly to encourage adoption, all existing registered domains should be grandfathered in, so they wouldn't have to put up a bond, whereas any future competitors would.
Finally, and this is the controversial bit, there would have to be some set of entities who were able to determine whether a domain had acted in a way that should forfeit their bond (and, optionally, that a domain had acted in a positive way long enough that the bond should be refunded). In practice, though, such a cabal already exists, which is the Big Three email providers (Gmail, Outlook, Yahoo Mail). Together they already have the power to destroy any new email provider, so we might as well formalise that by giving them the power to burn these good behaviour bonds.
Yes, the first was approximately contemporary with dinosaurs roaming the earth, before NCSA Mosaic was released and images appeared in webpages also known as the year 1992.
> We present a computational technique for combatting junk mail in particular and controlling access to a shared resource in general. The main idea is to require a user to compute a moderately hard, but not intractable, function in order to gain access to the resource, thus preventing frivolous use.
https://link.springer.com/content/pdf/10.1007%2F3-540-48071-...
Dwork C., Naor M. (1993) Pricing via Processing or Combatting Junk Mail. In: Brickell E.F. (eds) Advances in Cryptology — CRYPTO’ 92. CRYPTO 1992. Lecture Notes in Computer Science, vol 740. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-48071-4_10