I remember reading a report about a proposed RDF-enabled blogging platform; it was a project from the Semantic Web group at HP Labs Bristol. It looks like they built it - it's called Semantic Blogging.
I think the goal here is the same as that of Structured Blogging, although they've approached it from a different direction. Both projects have built publishing tools, but the StrB (which I can't just abbreviate to SB any more!) plugins focus on being able to publish as many different types of data as possible, and making it machine readable, whereas the SemB tool tries to do as much as possible with one microcontent type.
This makes the StrB plugins rather more useful to users... while the SemB tool is a nice vision of the future. I guess now we have to fold those features into StrB and all will be well :-)