> It costs $23 per month, and you just have to turn it on once and keep it running. Mailreach has hundreds of controlled inboxes to which they send emails from your server. They will keep conversations going and remove messages that landed in the spam folder.

in other words: Google (and other large providers) has distributed filter which kills domains that send emails which are often marked spam and supports domains sending non-spam emails.

But the spammers claim found a way around it: they have "hundreds" of robot accounts which pretend to be human and mark every email there as "not spam" and occasionally reply - thus even the spam-only domains can pretend to have good reputation.

I have very mixed feelings about this... From one side, this is 100% system abuse by spammers and I wish Google would catch this and nullified the contributions for the whole network... but on the other hand, the more random email-blocking heuristics Google has, the higher is the chance of false positive, that someone's real personal email is lost.