[kuschku]

Really?

Ever seen IRCCloud or Quassel?

Simple "one-click" "just works™" IRC bouncers, perfectly integrating.

[lmm]

IRCCloud costs money these days, and it's no more open-source than Slack in any case.

[davidw]

There's a difference between an open protocol and an open client. The latter... doesn't matter quite so much. The former is pretty important.

[lmm]

Slack supports connecting via IRC or XMPP.