Sparhawke, this is kind of freaky - sort of like "Close Encounters of the Third Kind" or "Twilight Zone" freaky. Here's why....
I don't believe I had ever heard of a trackback before today. At least I don't remember it. Just about 15 minutes ago, I was researching something else and came across a site that has a box specifically for trackbacks. I didn't know what that meant, wondered whether it could be related to a backlink, and came back to HP to see what I could learn.
I had just run a search here and had browsed through some old questions, forum posts and Hub titles, then came to the current forums to ask about something else; and then here was this thread, right at the top of the list. How cool!! [Great minds must think alike, right?]
I didn't learn anything that would answer your question - sorry! I'm not even that far along myself - yet. But I'll keep my eye on this thread, and post anything I learn.