Common Craft is a small company that does a great job of explaining web technologies in simple, easy-to-understand, short videos. I've used some of their videos in a classroom setting as a part of a lesson that incorporates a particular technology. The videos also inspire me to think about how to explain something in a way that conveys the idea in the simplest terms possible.
Their latest video explains what Wikipedia is and how it works.
http://commoncraft.com/wikipedia-video
