Another day, another Movable Type plugin. This one is kind of complex, so let’s start with the problem as outlined by Matt Haughey:
He later suggests that RSD be used to collect these TrackBacks.
PostedElsewhere sends those TrackBacks automagically. It uses RSD to identify where to send a TrackBack when someone comments on your site. It’s up to you to set yourself up to receive the comment TrackBacks.
Because it uses Movable Type 3’s callbacks, and because I haven’t upgraded yet, you can’t test it out here. However, I set up a blog with it installed at http://george.hotelling.net/postedelsewhere/. Leave a comment there if you want to test out your RSD file and TrackBack handler.