Try hush or filter. If you click on my username, scroll down a bit and you'll see the moderation options to shut me (or anyone else) up. There are helpful explanations of each option. Glad you're liking the site.
Thanks for the response. I'm doing badly at asking these questions. I tried the hush and filter buttons before. The hush button puts comments that person started on the bottom of the comments. Since a lot of people respond to other people comments, I would still see their comments. For me, the filter button just puts a line through the person's name, but I see their comments if I open a post. Supposedly their comments don't show up in my feed or chatter, but that's not how I find comments. From what I can tell, their comments still show up in the post the same way, just with their name lined-through. I didn't want to try the mute because I was afraid the person might be notified.
Hmmm... Based on the descriptions, I thought one of them might have done what you're looking for... mk forwardslash or thenewgreen did I read the descriptions wrong? Mute or block won't notify someone per se... But if you use them, the other person gets a "you are muted here" instead of a reply button - so yah, they quickly find out. Edit: I just re-read and see that filter takes your content out for my feed and chatter... But not from the post itself... Hmmm. I wonder if the kind of moderation you're looking for is possible?