Research interest: social information systems?

As I think about what I’d like to spend the next two years studying, I
find myself going between personal information management and
something (new? old?) that for lack of a better term I will call
social information management. Blogging, social bookmarking and
social networking aren’t quite personal-information-management topics,
but they aren’t quite groupware either. These tools support weak ties
with people outside your usual circles, and I’m fascinated by how much
we gain when we share information with strangers.