My initial reaction to Slack's change was that it's not a big deal. In the small communities I've worked with through Slack, we generally assumed that Slack messages are temporary, and we'd hit the former 10,000 message limit someday. We used email for more permanent communication, so the expectation of permanency wasn't changed.

However, it was interesting to see the company's data that is supporting the headline's assertion (in terms of migrations to the service after the Slack change). I'm also part of a smaller Slack group of a few people, and in abstract, it's understandable that it will be sad to see the older messages disappear. But then again, even in the tiny group, I always thought we'd hit the old 10,000 message limit someday, and never personally expected the messages to stay permanently.