With CBS's announcement that it has purchased Last.fm, I figured it was high time to take a look at some of the Personalized Internet Radio providers. When most radio people think of the concept of a "station" or online streaming - they draw the analogy to terrestrial radio. One station programmed by someone in an attempt to draw in as many listeners as possible. But the internet and advances in computing and bandwidth have allowed the idea of a "station" to be replaced.