I think open source communities won't happen on slack anytime soon. The story with the reactiflux slack showed clearly where they stand

I think it's just a matter of time until clojurians gets shut down as well

Some clojurians try to build their own chat software over at #braid-chat

Version 0.12 is now out with support for swapping vim keybindings with emacs ones! (if you like to torture yourself)