A couple old groups that I'm a part of have migrated off of yahoo to https://groups.io I think it's a step up in usability and interface.
In addition, I'm creating a Pay-what-one-wants alternative to FB gropus and Meetup and email lists ... It's sort of a cross between StackOverflow, Slack, HackerNews: https://www.talkyard.io (open source).
What do you like the most about Groups.io? if I may ask