> What matters is that I can deploy it on an existing infrastructure and still have control over the service instead of handing over control to a third-party

And its nice to be able to choose which apps you want to use on all the different platforms; and choose differently than everyone else. The app that works for me isn't necessarily the app that works for others, but I still want to be able to talk to them using the app I want.

I for one welcome slack competitors, self-hostable, open sources ones especially.

Check out http://sdelements.github.io/lets-chat/

Let's chat is really neat, I've played with it a lot but I have to say that the combination of not supporting OTR & The fact that it relies on MongoDB put me off using it in production to replace our existing chat server.

Maybe you'll be interested in Talqee [1] which offers a self-hosted version. It's coming really soon :)

[1] https://talqee.com

We're supposed to pretend a paid app will be competitive in this space.

hillarious way to advertise, chum.

There's Candy: http://candy-chat.github.io/candy/

In my opinion, it does matter. Slack is pretty and familiar, so an app looking alike is a good thing.

"Familiar", eh? To me it's still "that weird new hipchat competitor people keep talking about", but it's still something operating at a couple of degrees' remove: I've never used it or met anyone who uses it or heard of any reason to use it, and the one time I went to the website it wasn't clear that there was any way for random people to sign up for it. I'm curious why you see it as the established standard - isn't it basically brand new?

Slack built up $11m in annual revenue in a really short time, and is adding $1m in contracts every 11 days. At what's about $7/person/month, that's a lot more than no one.

http://www.businessinsider.com/slack-growth-after-one-year-2...

Maybe I'm just old and cranky, but to me both Slack and Hipchat are IRC knockoffs.

Let's keep in mind that Slack looks like IRC.

HipChat does this: https://www.hipchat.com/server