LATimes' book section "Jacket Copy" carried an item about LibraryThing introducing an iPhone app. LibraryThingLocal is used for mobile devices because you enter your location, such as your zipcode, and a map appears with the libraries, bookstores, fair/festival, and other book places (color coded by type). You can add your favorite bookstores and libraries, keep track of interesting events such as an upcoming author visit or your book club meetings, and connect with friends.
There is a "local members" option, which might be a way to publicize local librarians or book sellers. It does not appear to be a heavily-used option.