Captured in a post by Derrick Reimer on shutting down his company (hypothesis link) is a tidbit about how Slack works:
An engineer at Stripe told me about their careful balance of email, forums, and Slack. They recognize that Slack is not suitable for meaningful conversations, so they automatically delete chat messages older than a few weeks to discourage relying on it for long-term archival. In retrospectives, team members often reflect on whether they chose the right medium (email, chat, or forum) for various conversations.
Adding “chaos monkey” functionality to systems like Slack so you don’t use them as systems of record is an interesting tactic.
It’s definitely been part of what I’ve been thinking about with respect to not using chat for multi-time zone conversations. Never mind that the default mode of the chat interface is to notify people immediately.