So we should do some planning before we invite the world here...
We will want to consider some #hashtags as those allow us to have sub topics and also allow users to filter what topics they get emails in regard to. I set up this thread as an example of using #hashtags
Publishing it on Reddit as Gonzalo suggested could send us pass the 100 user limit before we have had time to get it organized and need to start paying for it.
It is currently set so that I have to approve all new members, if we have a few hundred dropping in all at once to check it out, that could be a lot of work. The nice thing about groups.io is that I can automate a lot of that, I just need to get everything set up for that.