I did a quick search for research on blogging as a writing genre, for a colleague who is involved in an European project. For interest, here are the main ones I found. If anyone wants to suggest others, put them in a comment to this posting and I'll assemble a larger list later on.
Amanda Lenhart, Aaron Smith, Alexandra Rankin Macgill, Sousan Arafeh, (2008) Writing, Technology and teens, Pew Internet & American Life Project http://pewresearch.org/pubs/808/writing-technology-and-teens
Susan C. Herring, John C. Paolillo, Irene Ramos-Vielba, Inna Kouper, Elijah Wright, Sharon Stoerger, Lois Ann Scheidt, and Benjamin Clark (2007) Language Networks on LiveJournal, Proceedings of the Fortieth Hawai'i International Conference on System Sciences, January Los Alamitos: IEEE Press http://www.blogninja.com/hicss07.pdf
Herring, Susan C., Lois Ann Scheidt, Sabrina Bonus and Elijah Wright. (2004)Bridging the Gap: A Genre Analysis of Weblogs (We)blog Research on Genre Project http://tc.eserver.org/25493.html
Herring, Susan C., Inna Kouper, John C. Paolillo, Lois Ann Scheidt,Michael Tyworth, Peter Welsch, Elijah Wright and Ning Yu. (2005) Conversations in the Blogosphere: An Analysis "From the Bottom Up" (We)blog Research on Genre Project http://tc.eserver.org/25492.html
Cornelius Puschmann (forthcoming) Diary or Megaphone? The pragmatic mode of weblogs. Language in the (New) Media: Technologies and Ideologies, September 3-6 2009, Seattle, WA, USA (accepted, to be presented).http://www.scribd.com/doc/15277764/Diary-or-Megaphone-The-pragmatic-mode-of-weblogs
Cornelius Puschmann (forthcoming) "Thank you for thinking we could". Use and function of interpersonal pronouns in corporate web logs. Heidrun Dorgeloh & Anja Wanner (eds.): Approaches to Syntactic Variation and Genre. Mouton de Gruyter.http://www.scribd.com/doc/15277768/Thank-you-for-thinking-we-could-Use-and-function-of-interpersonal-pronouns-in-corporate-web-logs
Cornelius Puschmann (forthcoming) Lies at Wal-Mart. Style and the subversion of genre in the Life at Wal-Mart blog. Janet Giltrow & Dieter Stein (eds) Theories of Genre and the Internet. Walter Benjamin.http://www.scribd.com/doc/15276171/Lies-at-WalMart-Style-and-the-subversion-of-genre-in-the-Life-at-WalMart-blog
Warschauer, M., & Ware, M. (2008) Learning, change, and power: Competing discourses of technology and literacy. In J. Coiro, M., Knobel, C. Lankshear, & D. J. Leu (Eds.) Handbook of research on new literacies (pp. 215-240). New York: Lawrence Erlbaum Associates.
Warschauer, M., & Grimes, D. (2007) Audience, authorship, and artifact: The emergent semiotics of Web 2.0. Annual Review of Applied Linguistics 27, 1-23.
Ware, P. & Warschauer, M. (2005) Hybrid literacy texts and practices in technology-intensive environments. International Journal of Educational Research, 43, 432-445