I've been using popfile to sort emails for many years, and it recently stopped working for most of my accounts, apparently due to an SSL problem. It hasn't been supported or updated for several years, and it's dead for me now. Basically, it's a proxy that analyzes all mail before it actually hits the inbox. It sounds like exactly like what the junk filter does with only junk/not junk.
Popfile uses as many buckets as you want to create to tell the email program which folder to use when storing the mail - mine had about 15, for work, family, clock repair, radio control, tech newsletters, spam, etc. After training, it's worked almost flawlessly for years. It modifies the message subject by adding [family], [clock], [tech], etc. Example: "[family] I'm in the hospital" when my brother sent exactly that message a few months ago. And a simple "If subject contains [family] move it into the Family subfolder" filter does the job instead of manually creating a complicated "if From contains Stuntz" or "if From contains Anderson" or "if From contains Larson" etc. filter for large families with several different last names. If you get an email from your mother-in-law that gets put into the Work folder, just tell it "no, that email belongs in Family, not Work." You don't even need to specify her name. The baysian filter will figure it out from the header & content of the email. You DO need to manually drag it into into the right folder, but you DON'T need to manually modify a filter to make future emails go the right folder. Training was remarkably quick & easy. It was pretty good after the first day of training, & gets better & better as you correct its mistakes. And the mistakes get fewer & fewer as it learns.
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