Basically in this attack, a victim (particularly a business or mailing list or NGO) is sending out bulk emails to which the attacker owns. Even sourcing this out to shady off shore click farms would work too.
Attacker then marks the victim’s emails as spam in Gmail/Yahoo/Outlook. The “AI spam filters” pick up on this new “spam activity” and will then mark future emails as spam or even delete them before reaching real customers.
After a year, company bleeds money on a quarterly basis. Ad departments wonder why there is decreased engagement through email. Technical departments are bamboozled.
Maybe a big company will be able to weather the storm or just ditch email altogether. But small companies would definitely take a hit. Even smaller NGO or political mailing lists would lose donations (assuming email was a significant source of new donations).
Probably a very low vector of attack tbh, but something that has lingered in my mind.