Like many other audio players, Windows Media Player rushes out to the Internet to find information for you when you play a CD. Some of this information, such as song titles and album art, is useful, but Media Player also identifies your copy of Media Player to the site where it’s getting data. Why? According to the help file, “The server uses this unique identifier to monitor your connection. By monitoring your connection, the server can make adjustments to increase the playback quality and to alert you about events that occur when receiving streams over the Internet.”
If you’re disturbed by this exchange of information, here’s how to stop it. In Windows Media Player, click Tools > Options and go to the Player tab. Notice the option that says “Allow Internet sites to uniquely identify your player?” Turn it off.