Funny you should mention this; I did spend part of the weekend answering some comments from 11 months ago (WHOOPS) and I apologized to all of them. Sometimes I do, sometimes I don't. (Apologize, I mean.) I'm usually able to stay on top of it, but when I miss comments, I feel like a jerk. That is not to say everyone should do that; my personal code of comment-answering doesn't really apply to how I feel about other writers and their comments.