Nice to see the number of libraries that already have profiles on MySpace and Facebook - I can see the value of this especially for building relationships with younger library users who are at home in the MySpace world. The blog by Meredith Farkas was helpful and she raises some very good points - for instance, about making your site truly 2-way (which is what Web 2.0 and social networking is really all about) by inviting comment, contributions, suggestions for purchase. We already talk at our users via our own websites - having a library portal somewhere like Facebook is a chance to talk with them.
With the right kind of promotion, this kind of outreach can move beyond the teen audience to embrace older users too - Kete Horohwenua (set up by Horowhenua Library) used Web 2.0 technology to reach out beyond their library users to the community at large, and did so in part by enlisting older contributors through promoting their site to the Senior Net people, who then went on to enlist and train others. They also set up workstations in the library itself that people without pcs at home could come and use to scan and post photos, documents, blogs - you name it - to the Kete site. It's a great example of local content built by its users - the library maintains a loose monitoring role, but the main contributors are the locals themselves.