The Yahoo group is not completely defunct. I’m not sure if I have the power to delete it, but even if I did, I don’t think I’d want to, as its page still has a pointer here. All the archives are gone, along with anything that had been uploaded (all of which I have downloaded, and most of which I’ve uploaded here), but the group itself still exists, and it’s possible to send email messages to it.
But with that said, I’m not at all sure the messages you received are legitimate. I didn’t receive them, and I should be receiving any messages from the group. Unfortunately, there’s no longer a way on the yahoogroups web site to see any history of messages to or from the group (even over the last day or two), so I can’t be certain either way, but I’d lean toward the messages being a form of spam. @Roy_Laroya is a member here as well; hopefully if the message is legit he’ll post here instead.