How do Yahoo/AOL's spam filters work (generally)?

Yahoo.com and AOL.com use a hybrid model that incorporates authentication checks, engagement signals, bounce behavior, and complaint patterns from their feedback loop.

These systems heavily penalize senders with inconsistent volumes or poor list hygiene.

Yahoo and AOL reward steady senders whose subscribers regularly open and click their mail.

It is a harbor that pays close attention to how often ships return safely and how satisfied their recipients are.