An overlooked aspect of trackbacks is that as a trackbacker you also get an inderect traffic measurement for the trackbackee. If we assume some kind of fixed clickthrough rate for the links you are able to plant elsewhere, then your referrer log gives you a good indication of the traffic to URL's you've trackbacked.
All this to say, that judging from my referrer log, Joe Kraus' long tail post and Adam Rifkin's microformats post are getting read a lot.
Kraus' post is brand new and interesting, so no wonder there, but Rifkin's post seems very consistent traffic wise.