Creating a presentation using Sketchcast can be a quick way to demonstrate a concept that would benefit from an explanation along with a creating a visual. Here’s an example of a math problem, an example of a chemistry problem, and an example of brainstorming and creating a editorial cartoon. In the first two examples I don’t think the creators used a digital tablet which would probably have helped. Its hard to draw with a mouse or a laptop trackpad–I know that its hard for me. The last example was created by an accomplished artist!
An additional feature is that you (or your students) can post comments but you have to create an account to do so (but that just takes a minute to do). Comments would be open to the general public so you might get comments from a wide audience which might greatly enhance the discussion.
Another great feature is that you can set up an individual channel and have a series of presentations within this channel. The channels have an RSS feed attached to them so if you used a feed reader (like googlereader, bloglines, etc.) you’d be notified if anything new had been added to someone’s channel.
Too bad that you aren’t able to use tagging to further identify your presentation and to help in searching. This would be a nice feature for them to add in an update version.