Maybe Slack already has this feature (I haven't used it in a couple of years), but it would be great if we could personally "downvote" users that have an unsatisfactory signal:noise ratio, and their comments would fade into the background colour of the page (like HN does with downvoted comments). Or use a decreasing font size or something to show me that I consider their input less important in general. This would on…
Well Slack is typically used for work so it's probably not a widespread problem but one thing you could do is open a #random channel so people can post all the noise there.
This was in a work environment and we had over 50 department and team-specific channels already, as well as a bunch of random noise channels. Funnily enough, it was the application developers who were the problem in this instance since they were being more of a hindrance than a help. Being able to mute them or quiet them down while I fixed their mistakes and was documenting the workarounds/solutions would have been very useful.
Perhaps it says more about that company than Slack in general though; it's the only place I've worked where Slack was used let alone considered mandatory.