I like facebook, but I understand why it's blocked. I see the value of it in schools, class groups and discussion along with photo and topic sharing, but you can't trust that all the students will stay on task. Honestly, are you going to tell me that you wouldn't do other stuff like quizes and talk to friends if it was unblocked? I really like facebook and go on it multiple times a day, but I still don't think we need it in school.
However, YouTube has so much educational value. That needs to be unblocked.