Allegedly, on or about 30 December 2013, Eddie G. O'Connor sent:
Every mailing list I've joined I have a genuine interest in, or it's a hobby of mine..(PremierGuitar.com.....GuitarFetish.com...etc) I see no real way that my email address got out TO the people who are using it as a spam receptacle! All I want is for the mail that I have no intention of reading to be sent either to my spam folder...or else the trash!
Ways of getting spam (and there's plenty more):
The mailing list gets hacked into, and someone steals your address. The mailing list sells your details. You've entered your address in somewhere (e.g. program registration), and that has leaked your address. You use your address in more than one place, one of them is public (like this list), and it's been harvested from there. You've received random spam.
If you had a used-for-list-only address, you can filter that separately than any other address. Just whitelist the lists you'll accept mail on it from. There's probably only a few, it's much easier to set rules to accept mail from A or B or C, than to block from A, B, ... to infinity.
And with mailing lists, there's usually list headers in the mail, that are better choices for setting rules against, than the list email addresses, themselves.