Social bookmarking ideas and patron use

I am fascinated by the potential of social tagging to increase the findability of online resources – be they items in a library catalog, websites, online journal articles, open access journal articles, etc.  Like many others in this course I can think of several ways we could implement social tagging tools into our services: adding subject-specific tag clouds into our online subject guides (I haven’t figured out how to do this yet), using a network of reference librarians to submit tags to a reference desk account to help us when assisting patrons, and building a community of researchers through a social tagging network, are just a few, not to mention just how much using social bookmarking tools can benefit us personally and professionally.  I have learned so many nifty tricks through the reading material, webcast and screencast that I can easily conclude that there are many more ways to implement social bookmarking into our services that I’ve yet to discover.  My only question is: do we know how much of an impact social tagging has had on the information-seeking behaviour of our patrons?  For instance, are undergrads using delicious?  Are faculty members?  Are we offering services using a utility that is not familiar to most of our patrons?  If not, it certainly creates a teaching opportunity.