> My question: Is it now the case that more of yahoo
> groups is dysfunctional than prsviously announced -
> i.e., is the mailing list functionality also down or
> degraded at this point?
I can offer my experience for what limited value it is. One group I belong(ed) to, and which we were copying to groups.io, simply ceased to exist according to Yahoo about November 7th. It showed up in my Yahoo groups list for another couple weeks, but now no longer exists there either.
The lesson I'm drawing from all this is that Y! is incapable of keeping such a system operating and their word means nothing. At this point I don't expect anything viable to remain of Y! groups after a year. They took a system that worked well and was still drawing attention and slowly ''fixed it'' until it was completely broken.