From the [site]:
"We call systems which provide perceptually-based social cues which afford awareness and accountability "Socially Translucent Systems." In such systems we believe it will be easier for users to carry on coherent discussions; to observe and imitate others' actions; to engage in peer pressure; to create, notice, and conform to social conventions. We see social translucence as a fundamental requirement for supporting communication and collaboration." (IBM T.J. Watson Research Center)
See Wiki:TomErickson as well, although it's very old (before he moved to IBM).
Most of the paper discusses a persistent-comment chat system called "Babble". In some ways, Babble has some similarities to "ThreadMode" wiki interaction. See http://www.pliant.org/personal/Tom_Erickson/AdoptionOfBabble.html for an updated study of Babble, including several interesting social/community observations (eg. WayLaying?, which is something that can happen at EverythingTwo)
Several of the other papers at Erickson's site are interesting, especially for their early views of the Internet and the Web. (For instance, http://www.pliant.org/personal/Tom_Erickson/GopherVR.html discusses a possible 3D environment for the GopherProtocol.)
Bradner, E. (1999) The adoption and use of 'Babble': A field study of chat in the workplace. In The Proceedings of the European Conference on Computer-Supported Collaborative Work (ECSCW), September, 1999.
Bradner, E., Kellogg, W. A., and Erickson, T. (1998) Babble: Supporting conversation in the workplace. Paper for CSCW 98 Workshop "Designing Virtual Communities for Work", Fall, 1998, http://www.pliant.org/personal/Tom_Erickson/Babble.CSCW98.workshop.html
Erickson, T. (2000) Putting the there there: Visualizing community data. Position paper for CSCW '00 Workshop on Dealing with Community Data. Available from http://www.pliant.org/personal/Tom_Erickson/ThereThere.pdf
Erickson, T., and Kellogg, W. A. (2000) Social translucence: An approach to designing systems that support social processes. To appear in Transactions on Computer Human Interface, ACM Press. Available from http://www.pliant.org/personal/Tom_Erickson/st_TOCHI.html
Erickson, T., Smith, D. N., Kellogg, W. A., Laff, M., Richards, J. T., Bradner, E. (1999) Socially translucent systems: Social proxies, persistent conversation, and the design of "Babble". In CHI '99. Available from http://www.pliant.org/personal/Tom_Erickson/loops.chi99.paper.html