Kasei is working on a Redland bakend for Movable Type - article and screenshots here
This entry points to some of the promise of the semantic web: Harvesting data from the vast amount of semi-structured data stores already out there. Blogging software already collects data in nicely structured ways, and stores them in databases.
Adding the ability to add slightly more semantic information comes at a very low cost in terms of time spent preparing the data.
Adding the ability of querying that data and linking information together using RDF comes at no extra cost in terms of human work once the software to do so is there.
Marking up all kinds of static information may be interesting, but the promise lies in MT Redland and similar applications that help us take advantage of structure that is already there but not made accessible or interoperable.
Imagine the untold terabytes of data tied up in databases that are not exported because there wouldn't be a simple way for people to make use of the data in a sensible way. Now connect it together, and the potential value of that data will in many cases skyrocket.