Our whole company has relied on this for the past few months in order to communicate with some of our clients, rather than invite them into our private Slack. It's been wonderful.
We have a shared channel too. It's great for times when you want to pull a client or a vendor into your slack for long term. You do want to be careful about getting pulled into slack (see this post and discussion from a week or so ago: https://news.ycombinator.com/item?id=20895853 ).
There's actually another use case where a vendor provides a bot and wants users of the bot to be easily able to file help requests. We wrote an app for that and outlined our thinking here: https://www.transposit.com/blog/2019.09.17-amazon-slack-shar...
How do you communicate about things related to the project, but doesn't need to have the client involved in? Do you have a separate internal channel per client?
My company has this, and I highly recommend it in general for security and data loss prevention purposes.
Any channel that may have external to the company users must have `-ext` at the end of the name and there should also be a non `-ext` channel for internal discussion that relates.
This ends up working really well because the channels sort together next to each other and you can tell very clearly from the name if you are talking "publicly" or not.
We do the same as other people replying, we’ve got a few shared channels with a major client, and alongside that internal channels related to work for them. You do have to be careful you’re in the right channel before letting rip about that one person at the other end everyone dislikes, but otherwise it works fine.
When companies are having to hire people and set policy to police their Slack channels for endless discourse by their employees, that is NOT wonderful.
There's actually another use case where a vendor provides a bot and wants users of the bot to be easily able to file help requests. We wrote an app for that and outlined our thinking here: https://www.transposit.com/blog/2019.09.17-amazon-slack-shar...