While Youtube is commonly known as a source of silly videoclips for kids, there is also a wealth of interesting clips for educators and others. I recently posted an example of using audacity as a speech therapy tool for individuals with autism. I've also been using youtube in the classroom for show relevant educational clips, including this one of Carl Jung talking about death.
The ubiquitous nature of video might frighten a few professors, such as the instructor whose anger episode in class was caught on tape by a student with a webcam; or the politician who doesn't think the world is watching, such as Congressman Charlie Bass of New Hampshire caught recently making horrifically hateful comments at a Republican gathering in Vermont (which one blogger called anti-semitic in nature).
I've been talking it up on campus on how professors can benefit from blogging, podcasting, and using youtube as a source of educational material. Professors who are "getting on the bus" are shifting from being straight forward lecturers to "assemblers of educational content." Teaching in the 21st century has got to include media literacy so that educators and students can connect with the planet and truly become global citizens.