Why is Yahoo group message still active when my Yahoo account has already expired?

Almost 5 years ago I made a few posts at a poetry group in Yahoo. Yesterday when I searched with my first and last name on Google, it returned my name on the homepage of the group. I went to the group's page and my name does not show up anywhere. The Yahoo account with which I had joined the group and made the post has long since expired. How come Google is finding me associated with that group? How can I stop my name from showing up with that group? Let me reiterate that the Yahoo account in question has expired due to inactivity. Thanks for any suggestion :)