Richard Ziade is experimenting with a video form he calls sketchcasting. A sketchcast is a recording of a whiteboard session plus voiceover. I’ve seen some very effective educational uses of this technique, and it’s interesting to compare Tim Fahlberg’s mathcasts to Richard Ziade’s sketchcasts. When Tim Fahlberg demonstrates the solution to a math problem in one of his mathcasts, the visual repertoire of numbers and symbols is fixed, and the creative contribution is sequencing and narration. When Richard Ziade delivers a presentation as a sketchcast, the visual repertoire is open-ended. We all know people who like to sketch and who communicate effectively that way. Richard Ziade is clearly one of them. Microsoft’s Steve Cellini is another. In meetings he invariably leaps to the whiteboard and draws pictures of the ideas being discussed.

It’s great to see all these forms evolving and — crucially — becoming more accessible. TechSmith’s Jing, for example, aims to make screencasting more spontaneous. SlideShare makes it easy to produce and share slidecasts, which are audio narrations of slide decks.

As words suffixed with cast proliferate — pod, screen, math, sketch, slide — it can all seem a bit bewildering. But with a range of choices, people who want to produce rich media can gravitate to the forms that match their skills and inclinations. And for those who watch and listen to these productions, it’s not complicated at all. You click the link, you watch and/or listen.