I massively disagree with #2. Unless your project has very little activity, synchronous or pseudosynchronous communication is a lot more efficient than async through email/discourse. It's also a lot more friendly to your contributors, it makes things less formal and more human.

Async shines when you have a lot of users, but only if it's very accessible (searchable). Otherwise it's just people repeating themselves constantly.

Also, longer rant on the IRC thing. For the past decade I've been using IRC as my central mode of group communication for all open source work. Last year and as part of my (open source) company, I've completed the switch to Discord.

I'm an open source die-hard and it bugs me that Discord isn't open source yet, but I believe this has a fairly high chance of changing (MUCH higher than Slack has at any rate). I would heartily recommend Discord for open-minded open source communities.

I'm now using Discord for everything. It has given me a unified interface for all my personal and group communications, easily searchable, with voice chat too (and video chat very soon, I cannot wait to never open Hangouts again). Needless to say, I'm a huge, huge fan.

Slack has none of that. The #1 thing that bugs me with Slack is the forced separate accounts for every single Slack instance. And you can't delete any of those accounts, you can only "deactivate" them.

Our open source community uses it. It works really well for us because we're a gamer-oriented open source community, so Discord is already pretty well known in that circle. On an ideological level, its API gives enough control over everything that goes in in it that I'm satisfied I could move to another service, should I need to. If anything, it's harder to move off IRC because there's no public logs, easy point of contact for the regular users, etc.

Also, I'm using Matterbridge to mirror our public channel to IRC: https://github.com/42wim/matterbridge/ (highly recommend everybody here checks it out; it supports a lot of protocols)

IRC has really disappointed me the past few years. I had a lot of hope that irccloud.com would offer a solution to IRC becoming irrelevant in the face of Slack and Discord, but it just hasn't happened. They're understaffed and don't have enough money coming in.

There's also a lot of ideological purity in recommending against SaaS "centralization" for comms but the truth is, it's not better. Last year my HDD crashed and I lost the logs for my organization's original channel going back to its creation... I'm very, very sad about that. Had I been using IRCCloud (or Discord) at the time, I wouldn't have lost all that. Granted, those companies could have, but the chances are lower than me fucking up.

This is the same reasoning why email is usually better off handled by companies whose livelihood depends on offering you the service, than by yourself.

Also like I said elsewhere in this thread, for a project using a Freenode channel and another using a Discord/Slack server, there is no difference between Freenode disappearing and Discord/Slack disappearing. Your host disappears, you have to find a new one, update tons of references and contact lots of users to let them know. On IRC, that's even harder. You can run your own IRC server, but very few do that, and those that do get less mindshare because connecting to yet another server is very annoying on IRC. It also costs you more, both in money and maintenance.