Altough you'll never ever see my response (since i'm on your ignore list), i am going to write something on your thread...
I have no problem with your ignore list. It's a free forum, i'm living in a free country, and if you chose to ignore me, it's your loss not mine. However, i do think there is one fundamental problem with your logic: i think it creates an even bigger mess than it solves.
Let me elaborate: A while ago, somebody asked a very good question (don't remember which one, i'm to lazy to go trough my complete post history to find the exact thread). I took a long time to give him a good answer (at least, in my eyes it was a good answer). Within the next couple of posts, DannyHamilton gave the same reply, repeating almost everything i said (but in completely different wording).
I was supprised, since DannyHamilton is an upstanding member of the community. Why would he just repeat my answer in his own words, just a couple posts after mine? I looked trough his post history, and found out it wasn't the first time this had happened. Then it struck me: he simply ignored me because i was wearing a signature, so he didn't even read my answer, he just gave the same answer as me because he didn't read a single reply in the thread. He was advertising his ignore list right in his sig. In other words: he made a bigger mess of the threat than i would have been if he had just seen the fact that the question was already answered, eventough it was by somebody wearing a sig ad.
Face it: if you're ignoring 80-90% of the people on a forum, you're going to give answers that were already given, you're going to answer to threads that are basically cold, and people are going to attack you for ignoring them (nobody likes to be ignored). In fact, your posts might be littering the forum by repeating the same thing that was already said by a sig-wearer.
That being said: imagine that you love swimming. Every day you go the the swimming pool, and you swim for a full hour. One day, a guy comes over and says to you: you love swimming, you're going to swim anyways, but if you wear swimming trousers with my logo on it, i'm going to give you $5 for every hour you're advertising my company. Would you refuse to put the guys logo on your swimming trousers? I know i wouldn't... I'd take the $5 and continue swimming.
That's exactly what i'm doing on this forum: i love posting, and since bit-x is giving me a little bit of money for every post i make if they can use my (otherwise unused) sig space: why not??? I'm not going to remove my sig add just because somebody would un-ignore me if i did... It's their loss, not mine.
Sorry for the rant: as i said, you're free to ignore me, and i'm not attacking you because if it. I just wanted to share my view on this topic.
There are undoubtedly some people making quality posts that have joined a signature campaign. They are the exception. My approach is not perfect, but I believe it is the best I can do.
As for DannyHamilton making a quality post that was substantially the same as your quality post: overall, I don't think it is a problem. His post confirmed your answer, making it stronger and more authoritative. I imagine that the wasted space was small compared to the sea of non-answers that (I assume) surrounded it.