Spam filter: Mail vs. Outlook
No contest. Mail seems to have quite an alert Bayesian filter (I assume) that uses the little “mark it junk” button to develop rules. It (rarely) gets something wrong—it was putting my email notifications from DragonGoServer.net in junk, but when I clicked the “not junk” button on one, that ended that mistake: apparently the “not junk” datum modifies the rule immediately.
Outlook’s spam filter, in contrast, doesn’t seem to work at all. Despite repeatedly clicking the “mark it junk” button for various messages—e.g., the endless series of spam in a Cyrillic alphabet I was getting—the messages continued to show up in the inbox.
