Excellent point! One of the many difficult things about viewing large quantities of data is that after a while it's hard to tell what you're looking at. The dataset used for this visualization consists of the four data points: Artist, Album, Track Name, and number of times played in iTunes. Normally you'd see a spreadsheet and you could sort by any of those four to see which tracks had been played the most, which albums you had, how many songs per artist, that sort of thing. In this visualization it's set up so you see in the large blocks the Artist name. Within each of those blocks the color is shaded in gradients to show you which songs per Artist have been played the most. So, in the upper left hand corner of the Disney block the darkest orange corresponds to the track I've played the most for the Artist labeled as 'Disney'. In this case, it's the Epcot Ticket Queue Music Loop first at 168 times played, followed by the WDW RCA Space Mountain Theme at 159 times played.
In other words, it's just a geek tool for seeing data in another format. One of the key things I do in my job is help people see their patterns within their data to make better decisions going forward and, based on this visualization, it looks like I've not listened to that Chris Calabrese 'Enchanted Tiki Room' rag time track very much at all.
