What we most miss about Pandora was the capacity it had to take a song or artist, and offer recommendations that were similar and totally new based on filtered criteria (of over 400 variables, based in a study called the Music Genome Project). We would input a song or artist, and were amazed at how often we would find new artists we never heard of before that we enjoyed.
The way he measures the quality of an internet radio site is in the amount of times he manually skips songs (an advantage internet radio has over satellite and terrestrial). With Pandora, it would run for hours.
CBS just bought Last.fm for $280 million, possibly an indication of where Internet Radio is headed. However, with this site, Enrique´s skip-track-rate was way too high. Story and Analysis
Interview with Tim Westergen, Pandora Founder