How does it do on Google? I'm obviously not expecting it to do amazingly and I know off site SEO can be done. But, assuming you are tracking that kind of information, are there posts consistently getting hits from our Google overlords?
As much as I like optionally-self-hosted tumblr-like idea, reasonable expectation of getting search engine to rank 'quite high' when, say, 3 fairly niche keywords combined appear in the title and throughout the post would be a benefit.