I get an unfiltered spam message in my inbox maybe once every month on average. I always assumed these are new campaigns with the newest "zero-day" exploits of

I get an unfiltered spam message in my inbox maybe once every month on average. I always assumed these are new campaigns with the newest "zero-day" exploits of the spam filter. Much more common is getting newsletters for which I have actually signed up, and marked as "Not Spam" in the past, delivered straight to my Spam folder. The number of spam messages I get in general, judging from what shows up in the Spam folder, varies wildly from week to week. Sometimes I'll get five over a two-week period, and then get a week where I receive about 15 per day.