Last night I got a chance to hang out with a majority of the folks from SocialText at Nancy White's House. Among other things, I learned about a resource by Chris Dent called Purple Numbers that I'd never heard about before.
In my words, it takes blog-style permalinks to the granular level. Using Purple Numbers, you can have permalinks to a specific paragraph of a weblog entry as opposed to one link for the whole thing. For instance, I can link you to a paragraph where Chris describes the original intent of Purple Numbers(The page scrolls to show the linked paragraph at the top- you can also see more Purple Numbers on Chris' blog).
I'm just starting to learn about it, but it seems to have a lot of potential.