I just checked, and you can mute an entire category, which means that you won’t be notified about any activity in that category. If you go to the "Slack Archives" category page then over on the right under your avatar icon should be a drop down with your subscription preferences for that entire category. By default it should be a hollow circle, i.e, “Regular”. If you instead choose “Muted”, then you won’t be notified about anything that happens in the “Slack Archive” category. I’ve check, and this appears to ensure that they don’t show up as “new posts” in your big post list, so they really are quite silent.
The only thing I have to make sure I do on my end is replace all the
@mcphee style user references with something else like
@ mcphee so Discourse doesn’t see them as user references. If I leave those on, then you get notified even if you’ve muted the category.
I think @everyone should do this since no one wants their “recent posts” list polluted by the migration.