I still don't understand why everyone is so excited about slack, it really doesn't offer that much more than IRC.
* File uploads
* Embedding portions of links (tweets, images)
* A very good search
* Multi-line posts
* Code-formatting, including multi-line posts, and also snippets.
* A mobile client that alerts you when someone mentions you.
* Scroll-back history when you sign on at any time.
* Syncing between multiple clients.
Yes, you could create a bot or modify an irc server to do this, and then find or write a client that will do all that stuff, and an irc bouncer can fill in for a lot of this.
But Slack does it out of the box. Zero extra work needed.
I like IRC, but if you claim that Slack doesn't offer anything more than IRC, you're either delusional or using an incredibly broad definition of IRC.
Nobody is selling IRC.
>We're sorry but Grove isn't currently accepting new customers right now.
I guess with that pricing structure they don't need to.