Ok, let’s give this a shot and see how it goes. 
I’ve just set up an online chat for Meteor users. It uses Discord, which IMO offers several benefits over other solutions:
- Slack is not built for open communities with potentially hundreds (or thousands) of users, as evidenced by when Reactiflux got removed from Slack followed by an email explaining that they had exhausted Slack’s resources. Reactiflux went with Discord.
- Gitter is ok, but the interface—speaking subjectively here—is subpar and clunky feeling. Not to mention, there’s just a single meteor channel and so it’s kind of a random hodge podge of discussions without much organization.
Discord has several attractive features:
- Optional voice channels
- Way better permissions system including creating roles and assigning users to those on either a global or per-channel basis
- Several channels a la Slack (so I’ve created, for instance, #blaze, #react, #redis, #mongodb, #off-topic, etc)
- (As far as I know) doesn’t wipe out chat history like Slack
- Free of course!
- Web, desktop, and mobile apps (all really well done)
For anyone interested in joining the group, hit this link. Unlike Slack, a single Discord login will get you access to any/all servers outside this Meteor one I’ve made.
If it fizzles out, I’ll probably abandon it. But spread the word and give it a go, even if you just plan on lurking there, that’s cool too!