That's basically Sendgrid or Mailgun or even Fastmail itself. They can all relay SMTP for arbitrary domains.
Such a product would need to have a ToS that states it can only be used for low volume personal and business correspondence, and have per-account rate limiting to enforce that. Doing it this way is necessary to avoid having mail treated as bulk.
I've tried relaying through mailgun to get mail to outlook.com, it does not work.
Jk, I just thought it was funny that we pay for services which were always seen as a free alternative to paper mail and stamps were a thing of the past.
On top of that, the costs of electricity are not the same everywhere (they are very expensive in The Netherlands, for example, than in the USA, and China is very cheap). Nor is it widely stable available everywhere (examples include India and Africa). Proof of Work is basically a waste of energy as well.
Maybe it's just been so long I'm whitelisted?
how so? the way i see it, only by making it too easy to use them. if you mean, they reject mail from (eg) dynamically assigned home subscriber IP addresses, you can blame spammers for that, not the big email players.
There's little to no additional security from having email on-site, and much hassle. Assuming you use google or outlook, the advertising bogeyman is just that - a bogeyman.
this is a super niche product, with a lot of useless industro-consumer design thrown in. it's doomed as a business and then where are you? back to gmail.
https://penguindreams.org/blog/how-google-and-microsoft-made...
The way most of these providers deal with spam is they slowly white-list IP addresses. When a company like Mailchip or Mailgun spin up a new server, it's always in a large subnet range they've purchased and they slowly start sending low priority e-mail through it to existing/known receivers and throttle it up to full speed.
If you're running a personal server that sends like 5 or 6 e-mails a days, well that's an issue.
The big players make it difficult to run a small personal server, but running a dedicated business or corporate server that sends 100s of e-mails per day is typically fine once it's well established.
You know what would be a better product? A relay SMTP server that works with Google/Microsoft/Amazon/Fastmail et. al. to pump e-mail from personal servers and ensures it won't get caught in spam filters.