"Pandora creates playlists of songs with similar musical characteristics -- it's not designed to make random jumps," chief executive Tim Westergreen said. "But what I think most excites customers is that it can truly help you discover
music that's similar to songs you already know and love, from artists you've never heard of."
Pandora's top-down approach to music recommen-dation is in stark contrast to rival Last.fm's bottom-up approach.
"The last radio station you will ever need," as it calls itself, uses an "audioscrobbler" program to collate information on the music that users play on their PC. It then builds up a musical profile that is used to match you to others with shared tastes, and so recommend songs and artists that others have but you don't.
"The recommen-dations work by finding music from users who are similar to you, who we call neighbors," said Last.fm founder, former Austrian radio DJ Martin Stiksel. "We then play you music they have listened to but which you don't have in your profile. So if you have 100 records, and 80 of them are the same, it's very likely you are going to be interested in those 20 that the other person has but which you don't.
"Pandora relies on a team of experts classifying the music, whereas with us it's the knowledge of the crowd, so to speak. [The crowds] know more about music, in our opinion, than a few experts."
This produces startlingly different outcomes, though each Web site makes its cash in the same way -- by linking listeners to online retailers. Last.fm, for example, brings up music people have in common, while Pandora brings up music that sounds alike. Tap in ambient pioneer Brian Eno in Pandora and the program plays obscure acts with similar sonic qualities. The same name in Last.fm throws up listeners who also had Talking Heads and Pixies records.
Encouragingly, most of the recomm-endation programs have one thing in common: decent sound quality from the streams. With Amazon continuing to provide poor quality clips for customers and iTunes only offering 30-second snatches, this has to be a good thing. Decent sound quality is also a feature of Artist Radio, Real Networks' recent venture into the music recommendation market. This limited offering builds a personal station based on the music of a fairly restricted and mainstream set of more than 200 possible artists. It's a weak alternative to the likes of Pandora and Last.fm, and doesn't allow users to skip a track they aren't enjoying.
Both Pandora and Last.fm also have another benefit: artists and labels can submit music -- providing a new way for acts to market themselves if they have been ignored by the major record labels.
And Stiksel argues that they also offer the potential to steer illegal downloaders into legal ways of accessing music. "We believe in streaming rather than downloading," he says.
While the recommendation sites may require fine tuning, he adds, they offer a fantastic way to navigate the ever-larger ocean of music. "In this day and age it's really difficult to find the music you like without having something like a music profile. Sites like this are going to become more and more crucial."