I think we need to be explicit, Slack isn't always conducive to the needs of open communities. Some of its features are extremely friendly to users, like having

I think we need to be explicit, Slack isn't always conducive to the needs of open communities. Some of its features are extremely friendly to users, like having the possibility of full message history retention and mobile apps. But the former does require you be paid, and the latter is also possible with other solutions.