Ask HN: Why doesn't Slack have single sign in?
It really annoys me that I have to maintain an account per each Slack community. Honestly it has actually put me off from using Slack. It's too much work. And the increased internet footprint bothers me, I'd like to be able to instantly vanish from all Slack communities in one click.
Single sign in seems like a no brainer to me. Why do they insist on new accounts? I think it's likely that it's because organisations can manage users by their domain name - it's possible to have a blanket rule that allows users to create an account for a team if they have an e-mail address from that organisation. That said, I'm surprised they've not let users associate all of your Slack team accounts with a single account.