These images represent an attempt to visualize 40 different iTunes libraries, geographically spread through the US.
As the author explains: "I contacted 40 friends of mine and asked them to send my a copy of their iTunes music library file. This is the file that contains all the information regarding the songs, artists, albums, and listening habits for a digital music library. I wrote a PHP program that threw all of the libraries into a database and located each library based on the latitude and longitude of where the person lives. A vague form of the United States can be seen (Seattle in the upper left, NYC on the right). Lines are drawn between the albums that one person has in common with another. Each album is represented by a small dot in the Library graph. The point's grey scale value is determined by the frequency with which the album has been listened, the tone of the line connecting albums is an average of the starting and ending points."
A total of 14,132 lines make up the image.