I definitely agree that screencasts or just straightup video podcasts would make some topics much easier to cover (for instance I'm working right now on an intro to WireShark, and that's the sort of thing that would be much easier to do via a video). Possible limitations would be server costs (videos take up space), format/encoding/size consistency (all of which would be nice), and the fact that this is Hacker Public *Radio* ( SISTERSITE )