A couple of people responding to my post, "Distracting Technologies," pointed me to this Bud the Teacher post: "Would you please block?" It's well worth sharing and considering:
Ever since we opened up lots more of the Internet in our school district earlier this year, the district has received several requests from teachers and other staff to block resources that are distractions in the classroom. I’ve written a stock response to those requests that I thought might be worth sharing. It’s my hope that their requests and the conversations that come from this response lead to changes in classroom practice.
Here it is:
Thanks for your question. When we implemented our new filter this school year, we looked at all the things we were currently blocking, what things were required to be blocked by law, and what we were blocking that we shouldn’t be.
What we’ve decided is that we will no longer use the web filter as a classroom management tool. Blocking one distraction doesn’t solve the problem of students off task – it just encourages them to find another site to distract them. Students off task is not a technology problem – it’s a behavior problem. It is our intention that we help students to learn the appropriate on-task behaviors instead of assuming that we can use filters to manage student use. Rather than blocking sites on an ad hoc basis, we will instead be working with folks to help them through computer and lab management issues in a way that promotes student responsibility. We know that the best filters in a classroom or lab are the people in that lab – both the educational staff monitoring student computer use as well as the students themselves.
This opens up possibilities for students and staff using websites for instructional purposes that in the past were blocked due to broad category blocks. It requires that staff and students manage their technology use rather than relying on a third party solution that can never do the job of replacing teachers monitoring students.
That said, we will still block sites that are discovered to violate CIPA requirements. If you discover one, please do not hesitate to share it with us. Also, if you discover a site that shouldn’t be blocked, please pass that along so that we can open it up.
I hope this makes sense. I’d be happy to speak further with you if you have further comments or questions.
If we are serious about trying to remove all distractions from our classrooms for easier classroom management, we might be better starting off with pencils and paper (doodling), windows, announcements coming over the intercomm, and, of course, girls.
Of course some kids might say we should remove the teacher who distracts them from their personal online information seeking activities.
Thanks, Bud, for a great letter and post.

http://www.informationisbeautiful.net/visualizations/the-hierarchy-of-digital-distractions/