Sorry, but that is just obvious flat-out bullshit. Have you tried using Psi (an XMPP client) to communicate with a user using the Slack client (well, after thi

Sorry, but that is just obvious flat-out bullshit. Have you tried using Psi (an XMPP client) to communicate with a user using the Slack client (well, after this change, obviously ...)? Did you have any success with that? No, of course not. In other words: Slack is obviously not a product where you can "count on all the clients seeing things the same way and supporting the same thing.". Slack works with exactly one client at the other end, so it is bullshit to claim that it "works the same with all clients", when in fact it works with exactly one client, and that's it, with other clients you get exactly no interoperability at all. And it is bullshit squared to pretend that that is somehow an advantage over other technologies: No single client using any protocol provides an inconsistent featureset or interface. It doesn't matter which single client and which protocol you use, you will always get a consistent featureset and interface. That has absolutely nothing to do with Slack, but only with the fact that you standardize on one client.