A US study (http://pewinternet.org/Reports/2010/Social-Media-and-Young-Adults.aspx) has indicated that younger internet users are losing interest in blogging and switching to shorter and more mobile forms of communication. The number of 12 to 17-year-olds in the US who blog has halved to 14% since 2006, according to a survey for the Pew Internet and American Life Project.
Mashable write up of our Twitter article: Alan Cann, Jo Badge, Stuart Johnson, Alex Moseley. Twittering the student experience. ALT-N, Vol. 17, October 2009. http://newsletter.alt.ac.uk/xrctg5ovlfkimsphpsy77s