Right off the bat, I can tell you that one of the strongest advantages of social networks like Facebook or MySpace is that the patrons (Especially the kids) are already knowledgable about it. Or, for that matter, more experienced than we are. (Again, especially the kids) So, any library program involving Facebook or MySpace would simply be a "Plug in and play" situation.
When I looked up "PCL Library at UT Austin" on Myspace, It said that it was "Invalid, user has either cancelled or has been deleted". Odd.
It's hard to picture the Library of Congress having Twitter. When you hear "Library of Congress", the first thing that leaps to mind is historical documents written on centuries old parchment. But, it is very usefull. Lots of "Bulletin Board" style notifications, which I could also see the Little Elm Library doing.
Part #8 of the assignment was pretty easy, since I'm already signed up for MySpace.
I really don't see too much of a problem with privacy online for myself personally, since I honestly don't go online that much. However, if we choose to do this as a library program, a warning about posting should be included.