MRTs have the potential to make teaching a more public and less isolated practice. An increasing number of schools now use "walkthroughs" to get teachers into each other's classrooms. But there are logistical and practical limits to their use (schedules, the often fly-by nature of such events, the difficulty in observing teaching outside your own building). MRTs can overcome many of these issues by giving teachers and administrators access to a much wider array of classrooms; by allowing them to slow down, back up, pause, and look at certain features of the lesson again; by following work over more than one lesson; and by accompanying the video with other materials that deepen and enrich the conversation. New York City, for example, is planning to create a best practices Web site that can be used by teachers and school leaders districtwide. MRTs may be particularly useful in working with prospective teachers and school leaders, in networking across sites, in ongoing professional development, and in educating the public about how complex a job teaching actually is. They can also help create a common language, a shared orientation, and a more systematic vision of teaching beyond random acts of artistry. There are, of course, potential downsides. Lots and lots of people now have lots and lots of videotaped lessons (including the National Board for Professional Teaching Standards) without a clear idea of how to best use them or what they actually illustrate. Deborah Ball has also expressed the fear that people could get very good at "analyzing" videotape without actually learning how to act or change what they're doing when they teach.