I really enjoyed what i have done so far working with facebook. Although it does discourage anonymity, most people can find out your history and life by paying a small fee on the internet.
The cons is the anonymity, but the pros can be endless. You can connect with old friends and neighbors, you can meet new people with similar interests, you can learn from others about where they live and what they like to do.
I will probably use this personally as well as professionally. Personally in the sense that i will try to contact old friends. Professionally I would use it to help others get connected to others as well as learn about the new and exciting things going on in the libraries across the world. I have already done this with an aunt who i found out volunteers in a libary.
Facebook has potential an endless marketing potential including but not limited to the wealth of knowedge i can gain from other Youth Services Librarians. I am new to the field so i could always use new infromation.