I'm part of the JISC funded project LinkSphere at Reading University. They are building an online social media tool to do cross institutional repository searching, and facility research relationships. While the guys there are getting up to speed on programming the first demos, we set our research assistant, Claire Ross, a task: why not write up a paper on how people use social media. And why not do one on twitter. And why not study how Digital Humanities folks use it, within conference settings (thereby giving a nice corpus on which to base the study).
The results are here. A nice full, paper which has been submitted to a journal for consideration. Let us know if you have any comments!