This nifty free tool could allow mathematician, statisticians, engineers, etc. to present and solve equations online while explaining the process to students.
A new site called Sketchcast launched last year - it's a tool for bloggers and others to create a presentation to express an idea using a sketchpad and (optionally) a sound recording, and then embed it into a website. Sketchcasts can also be subscribed in iTunes and RSS readers via a feed.