I’ve heard the complaint that when moderators split threads, it feels like the tangential thread is being hidden or punished in some way. That’s not the intent, of course — we do this when there’s a significant topic that diverges from the original conversation so that both conversations can continue without confusion.
There is a message saying that a topic was split out, but it’s pretty subtle. For example:
I think it might help if these “signposts” were a little obvious. I’ve modified the Testing themes (which you can try in your preferences) so you can try it out. My change increases and emboldens the text slightly, and adds a colored highlight to the side, like this:
With my eyes fully recovered, and my mind cleared, I think there’s no real use for additional emphasis. The message is subtle, but clearly marked different from other messages. Too much emphasizing adds noise to visual communication. (I’m doing some pre-press from time to time.)
Not a game changer of course, but I think the bold is useful to direct some more attention to the split, which helps to further mitigate confusion caused by splits. In the end, a split is more impactful on the subsequent development than just a post, and many users just skim through until something catches their eyes, which again can end up in confusion (or loss of information relevant for them) when they overlook the split during skimming. I don’t see a disadvantage that goes along with it. So I like it.
FWIW I’ve currently turned off the emboldening but kept the embiggening, so we can see what that looks like. My concern with bold (and even a larger font, really) is that it looks too much like a header for the following posts.