I teach at the intermediate level, but the firewalls are the same for all levels in my district. We have a firewall that rivals the Great Wall of China. Everything with the word "blog" is automatically blocked. We cannot access any social media sites while on the school network - Myspace, Facebook, Twitter - you name it, it's blocked. I can understand YouTube being blocked, but TeacherTube is as well which doesn't bode well when contest videos are uploaded there. We cannot access sites with streamed videos or music with the exception of Discovery Education and the Smithsonian. However, I am very grateful that wikispaces is still open for us because that's an awesome collaborative tool that we use with students and fellow colleagues. Several teachers on my campus have a wiki and I even created one for the teachers so that we have an online forum for discussion.
However, I found that the use of sites that are blocked by my district still attract students who will work on assignments at home - eBlogger and YouTube - which just goes to show you the motivation of students who are so closely tethered to the digital world. They don't sweat the firewall.
Up until last year our Board's policy was to block everything. They have recognized that students are using technology outside of school and that we need to teach safe and appropriate use. They have decided that access to current information outweighs the negatives. It took some training, but the kids know the rules and the consequences of not following them (banishment from the lab). We have blocks for inappropriate sights and to safeguard against viruses.
Unfortunately we must block Social Networking sites to comply with CIPA. They include the world, so the content is not something we can make available for our students. With that said, we do allow K-12 Centric sites that are moderated and have exclusive K-12 content. We are implementing Google Apps!
We are also working on providing Role Based Access Controls, RBAC to allow all staff to access Youtube as an example. There too many good training resources to not allow teachers this access, to share with students. Since even Youtube's content can be rather trashy for a K-12 setting, we have no choice but to continue to block it for students.
Besides CIPA, there is liability exposure and a high volume of malware directed at sites like facebook, with 600 million users, yes the cyber criminals target it.
On liability exposure, lets just say you have all social sites wide open; a student finds an obscene video, shares it with another student! The student goes home tells mom, the local, News, CNN, etc
Suddenly a lawyer calls the school District and points out how the School was negligent and should have known that these videos were available. The school gets sued! Unfortunately this is the reality of our litigious society!
We will continue to add more social networking in a balanced way, in a way that enables the process of education while still protecting students and our tax payers from avoidable lawsuits.