Link from TerryP's blog
I think this is why I have so much fun working on PlannerMode. I have a clearly-defined set of users in mind (mostly the mailing list) and I love threshing out interfaces and features with them. It's not a large-scale application and it certainly doesn't appeal to the masses, but it can be quite powerful when you get the hang of it.
Hey, Emacs is like that too. =)
Open source supports situated software very well, as you can tweak something existing in order to fit your needs.
By the way, the author taught a class called Social Software.
Must forward to Dr. Rodrigo. This is her kind of thing.