If the well-worn idiom "a picture paints a thousand words" is true, then how many words does a video paint?
Video is everywhere on the interweb nowadays. As connections have speeded up, the technology has allowed this medium to flourish and become mainstream. We are all comfortable taking in new information in video format - there's a reason that television has been so wildly successful.
One place that short video clips can be really, really useful is for providing technical support to computer users, particularly software support.
Videos for this purpose are often called "screencasts" and there are now lots of services that can be used to make professional looking screencasts. My current favourite is Screenr.
So, next time you have a customer on the other end of the line, and you are struggling to explain what they need to do with some software, try saying "I'll send you a video showing you what I mean in a few minutes". It's much less stressful for both parties.
Of course you could achieve your purpose using screen-sharing but your video can be re-used again if needed.