Probably not very helpful/informational but:

I work for VzM, but not historically directly on Yahoo products (product teams have been merged/consolidated etc. over the past few years, but there's still strong tendencies toward products people came from).

So I wouldn't be very clued into what's happening with Yahoo Groups internally. And I've heard nothing about this internally. At all.

As it stands, it's 2:30pm in SV, VzM is top of the HN frontpage, and not a single soul has mentioned it yet on internal Slack.

Will see if I can find out more.