I like the ability to create sidenotes. What are sidenotes? You can go here to find some JavaScript code that implements them. Neat.
I’m not especially fond of the existing CSS. I think boxing text that can be word-wrapped is very ugly. I might take some of the ideas embedded in this and adapt it to something closer to what I imagine.
Addendum: What do people think about the ubiquity of JavaScript? Is it hopelessly wrong to require it to view your weblog? It’s not like I am going to any special effort to make my blog particularly nice to read with small screen devices like cell phones. Should I?