It's probably far from a secret, but the University of Minnesota library offers everyone in the University community a weblog of their own. UThink has been around just over a year -- they celebrated the service's first birthday on April 12, 2005 -- and has an impressive level of use:
Just think what a powerful communication tool your library could offer your user community. Whether for book discussions, community organizations, "birds-of-a-feather" gatherings among patrons with similar interests.... The possibilities are amazing.
