www.soulandjazz.com launched its unique, legal and commercial free podcasting service on the 18th May, 2009, featuring music across the spectrum of soul and jazz from the last 50 years.
A wave is a disturbance. It is an interruption of space. So everything is just perfect until you get an idea that competes with the pre-existing emptiness for your attention. And this disturbance propagates through space, often transferring energy.