I use Slack for work and like it. I used to use it via IRC but the experience is much better in the browser.
I agree that open tools are preferable to closed ones. However, it’s tough to get people to use IRC and XMPP. Slack took off because it created a pleasant, easy-to-use user experience. It’s not ideal, but it’s often better than email.
I think chat is a tough sell for many users. I grew up with it but I that experience is specific to people of my generation. For older and younger users, I think chat is still sort of a weird thing.
Still, I’d love a really good chat solution, that supports file uploads, built on XMPP so people can move when companies make choices all of its users don’t necessarily agree with.
Slack’s bait and switch | Opkode