Having posted the example from Matthews Keys's Twitter work in the summer, I have spent the past month paying attention to news and other events that are live-blogged using Twitter.
There appear to be two distinct categories:
1. Reporter/writer goes out into the world, observes something, writes the play-by-play. This would fall under my original "reportage/observation" category.
2. Reporter/writer monitors another news or information source and provides readers with a play-by-play. This is what Keys did; it's what the Toronto Star's Daniel Dale is doing this afternoon with Toronto mayor Rob Ford and his councillor-brother-sidekick-mouthpiece Doug on their weekly talk radio program.
This secondary media coverage--usually used, as far as I can see, with live television or radio broadcasts of interview/talk shows, is an interesting use of the micro-blog.
Examples from Daniel Dale's 1010 Tweets:
NewsTalk 1010 host Jerry Agar will be a guest on the NewsTalk 1010 show hosted by the Fords today.
The first 20 minutes of the show have been devoted to the Chicago trip. The Fords believe it was a major success.
Blake Hutcheson, Oxford Properties and Build Toronto chair, is now on air talking about the value of the trip.
About an hour into the show, we're done with Chicago; Fords are now interviewing Hadfield, talking Summit Series.
I plan to keep a list, here, adding to it when my Twitter feed brings in other examples of this kind or people suggest good examples of Twitter as a source of live but moderated media.