Everyone has their "cast" that they like. Some people follow specific thought leaders, while others catch up on their favorite tv shows news. Podcasts /vcasts allow us to expand the roll of the blog. They allow us to create auditory monologues that people can listen to while doing other things.
The podcasts/vodcasts allow educators to reach student in a different way. By making "casts" available for course, no longer does a student have to rely on their friends notes if they are absent, or stress that they missed a section of the class to go to the bathroom.
Classrooms full of students can be engaged or inspired almost ignited prior to the teacher ever opening his/her mouth. The use of a vodcast could allow students to begin to ask questions and actively engage with their teacher or professor in a dialogue about the topic.
For many who used videos or dvds in the classroom, the use of casts is a mere extension. What makes this medium better is that the teacher can create media that fits his/her needs. The drawback is that teachers will need to worry about what is taped, how they sound, and how important are the production values. But, the pros certainly out weigh the cons.