The in-thread activity is highly annoying and utterly borks ability to follow a discussion. I've always hated that.

The in-forum activity highlights areas of current activity. It's mildly noxious where old, long, threads are dredged up, some sort of contextual trimming might be useful in this case, but that can be handled seperately. I don't like having to hunt downpage for current, but buried, threads, under a bunch of static material (no, not you, Wade).