Sketchcasting is a tool to communicate something online by recording a sketch, optionally with your voice speaking. Any sketch can then be embedded on your blog/ homepage for people to play-back, and you can also point people to your sketchcast channel here.
Here is my very first attempt to draw with this tool (please don't flame :-) ) where I tried to explain the technology GenomeHip used in my company to find the region(s) involved in a genetci disease. The approach relies on isolation of identical-by-descent regions from relative-pairs sharing the same disease.
Added Later: http://www.imaginationcubed.com/LaunchPage is far more powerful but you cannot blog your drawings.