The alternative is pretty much only online forums. Which imo. doesn't offer a lot of advantages, and most forum software is exceptionally bad (though yes, a few new and nicer ones are coming along)

Discourse NodeBB and Vanilla comes to mind

None of them appropriately support mailing lists, though. Email-based communication is a big deal for devs which contribute on maybe 5+ projects at once and have to manage comms in one central place.

As for Discourse's mockery of a mailing list mode, let's not even talk about it.

Are you familiar with DFeed [1] used by the D-Lang forum [2]? It is, in my opinion, one of the most usable web frontends for mailing lists (as well as a few other sources).

[1] https://github.com/CyberShadow/DFeed

[2] http://forum.dlang.org/

Never heard of it. Looks quite good. I will keep an eye on it, thank you.

If you're managing 5+ projects at once, your inbox must be a train-wreck of garbage from these mailing lists.

GitHub has email notifications for issues, but you can opt out of any particular discussion if it gets too pedantic or doesn't relate to you. This helps massively reduce inbox clutter.

The thing that bugs me about mailing lists the most is you get all the email, all the time, forever.

>If you're managing 5+ projects at once, your inbox must be a train-wreck of garbage from these mailing lists.

This is a total non-issue. Mailing lists support daily digests if you want that, and email clients support folders and filters if you want that instead. Nobody managing 5+ mailing list-based projects at once is dumping all of that into an unsorted inbox.

> and email clients support folders and filters if you want that instead.

Because who doesn't like mucking around with their client's filtering?

Ever heard of Sieve? ;)

Ever heard of it's 2015 and I'd like to be able to opt-in to specific mailings if necessary.

Isn't there a decent mailing list package that hybridizes a GitHub "issue" type system with a traditional "email firehose" approach?

Mattermost is a free and open-source alternative to Slack, giving users publicly searchable archives, great for sending images, files and code in chat. http://www.mattermost.org/

I have never used mailing list so I'm probably naive, but what about github issues?

Mailing lists are not just about issue tracking (and really shouldn't be about it). There's general discussion on them, release announcements, etc. pp.