[dr_win]

Back in the old days if the Internet, there was no cryptocurrency. I strongly believe (crypto)payments can be used as a pretty effective anti-spam measure in the future.

[alwillis]

Agreed; the goal is to make it too costly to spam.

[jlgaddis]

I think this falls under the "e-postage" variant of the Final Ultimate Solution to the Spam Problem (FUSSP).

https://www.rhyolite.com/anti-spam/you-might-be.html