"listeners will be pleasantly surprised to discover songs that they never knew they already liked."
 
This point is worth thinking about: the irony is that by matching songs based on such "genes," Pandora allows people to make serendipitous discoveries that are primarily based on similarity. The site encourages exploration within a certain range, but maybe it also creates an environment that discourages new musical discoveries outside of the listener's comfort zone. Does this make the listener's world smaller, instead of larger? This dual restriction and facilitation of exploration enables the user to tightly control what kinds of "surprises" he/she encounters. Is that discovery at all? I think this kind of tension exists in archives and databases as well. Part of the challenge of designing such a resource seems to be asking oneself how to best manage information in a way that negotiates between chaos and rigid order.