This is funny and sad. I'm sure it's a side effect of Yahoo's spam system, which flags as spam not only senders whom you, the user, flag as spam, but also those which its other users flag as spam. This is a real problem, because it appears that lots of people subscribe to a mailing list, then tire of it, and instead of formally unsubscribing, they just flag it as spam so they never have to see it. That's fine for them, but then Yahoo flags the mailing list as spam for *everybody*. Which sucks for everyone who still wants to read the mailing list, and the mailings keep ending up in their spam bin. It keeps happening to me with OWW list posts, for example. It also happened with a gmail account and a medical mailing list.
Ugh. Dumb and lazy people screw things up for everyone else. But what else is new in the world?