It was interesting to do this lesson, researching libraries on Facebook. I found that both my undergrad & grad college libraries are available as apps on Facebook:
Alvernia Library Search
BISON Catalog-UB Libraries
I added some library apps to my profile: Library Gifts, Librarian, My Library Thing, National Archives Libraries & Museum. And I "became a fan" of: Library Journal and Internet Public Library. Finally, I joined some library groups: Libraries and Librarians, Librarians and Facebook, FacebookAppsForLibraries, Library 2.0 Interest Group, and Don't Mess With Me, I Worked in a Public Library.
I noticed that some libraries have created and made available a Ask A Librarian facebook app for their library systems.
I think it would be great if we could get the Public Library of Youngstown & Mahoning County added as a profile page on Facebook. Plus, maybe Ohio's Know It Now could be added as an app on Facebook.