With a motto of "teach the world", TeacherTube is designed for education. So far, I have found this site to be slow, but it has promise. You can make comments, rate videos from 1-5 ‘apples’, and tag videos/search by related tags. But most importantly (which helps to keep it safe), you can flag all inappropriate videos.
Until we can convince school districts that technology is a tool that has to be taught how to be used properly and safely (like driving a car or crossing a street), TeacherTube may allow you to post, view and share videos with your students.
This video (and its byline) sums up these concerns: [Link]
"Technology is not the enemy — ignorance is. I am concerned that we need to intentionally teach students the technology skills they need to know. They do not get it automatically nor do they learn it at home."