Hi Ahuka,

As you know I am enjoying the series.

I don't think that charging for messaging, however small is the answer. It is socially unfair as it imposes a financial barrier that many may not be able to afford. To quote my mother, "It's not a lot to have, but it's a lot to want". I had to send 100 applications before I got my first job, that would amount to $1 in your proposal. Now put that into context when your income is $41/month, and you see it excludes the poorest nations.
https://www.worlddata.info/average-income.php

In any event it was tried with email back in the 1990/2000's and failed.
https://www.geek.com/news/yahoo-introduces-paid-for-e-mail-service-called-centmail-872762/

However it didn't stop companies in using the idea for profit.
https://www.eff.org/deeplinks/2006/02/aol-yahoo-and-goodmail-taxing-your-email-fun-and-profit

I also have concerns on any solution that requires a verified identity in order to participate. As soon as you do, you stop been federated, and start been walled gardens. Not to mention the registration process that would be needed, and then would need to be taxed, and surely limited to authorized providers, etc etc.

I'm glad of the chance to think about this, so please keep them coming.