Wistia is a video hosting service - think of a YouTube-like service where you control all of the sharing, analytics and security.  You can host up to 3 videos at a time for free.  It is a great tool for teachers, but not just because of their hosting service.

The best use of Wistia from a classroom perspective is their outstanding video tutorials.  Check out their Learning Center and Blog for simple ideas that will help you and your students can make better videos today.