A plague on both of them!
Yahoo have gone to a so called "neo" format where just about everything has been changed, most noticeably in their groups system where significant liberties have been taken, and moderators are left trying to sort out the train wreck which has resulted.
I will be looking for a more stable and functional vehicle for my two groups in the future. Quite simply
Mailman would do nicely in my observation- I just need to find the machinery to host it. If it costs, then so be it.
Bah! Humbug!