iTunes Tracker is a client application which allows users to connect to a database of shared iTunes 4 libraries. The database is based on how many people are connected and have iTunes 4 sharing enabled. This list is displayed on your computer allowing you to access any of the shared iTunes library on the list. A simple user interface allows easy navigation and reduces the amount of window clutter.
iTunes Tracker detects if you're sharing your iTunes library. If your library is shared then your address is added to the list of shared iTunes libraries. This list is downloaded when a client connects to the central server. The more shared libraries the longer the list. With more users comes more selections and so on.