MovableType have released version 2.21, which finally introduces support for mySQL and also comes with an intriguing new feature called TrackBack. I’m stil trying to figure out exactly what TrackBack is.. so far I’ve figured out that it invovles embedding RDF information directly in to your blog which can then be combined with a “ping” to other blogs to inform them that you have linked to them, and give them additional information about your blog for display on a special TrackBack section for each of their blog entries. Scott Andrew has already implemented it and many other MovableType blogs are setting it up as well. TrackBack has its own blog, which has an interesting entry hinting that TrackBack could soon become part of a system for distributed taxonomies (a problem that XFML is also looking to solve).
I’m not completely convinced by TrackBack. The implementation includes RDF embedded in blog entries which breaks XHTML validation (a problem the trackBack developers are already working on—could comments around the RDF data help here?) and I can’t really see any advantages over standard referral tracking as implemented on diveintomark. I plan to implement my own referral tracking system soon and I will almost certainly model it on Mark Pilgrim’s, although I hope to provide additional information about the referral source gained by parsing their HTML. That said, I’m still trying to understand exactly how TrackBack works so I will reserve judgement until then.