I moved to FastMail lately and was pleased to discover that you could have some control over the spam filter[0], as well as useful advice: Note: We recomme

I moved to FastMail lately and was pleased to discover that you could have some control over the spam filter[0], as well as useful advice: Note: We recommend that you do not mark your Spam/Junk Mail folder to automatically learn "As spam". This can create a false positive feedback loop. Imagine an email is incorrectly classified as spam, put in your Spam/Junk Mail folder, and then learned as spam. That means future emails that aren't spam are now more likely to be incorrectly marked as spam, sent to your Spam/Junk Mail folder, and learned as spam. Only mark folders to learn "As spam" if they're folders you manually move email to. Now on top of that say you're using a MUA and its own spam filter runs atop of that, and decides to move a couple of legit stuff to Gmail's spam folder, triggering the server-side spam learning process. Surefire way to screw the whole thing up (happened). [0]: https://www.fastmail.com/help/receive/stopspam.html?u=b83140ac https://www.fastmail.com/help/receive/stopspam.html?u=b83140...