if you download the song onto your computer, it will have a serial number. if you then copy it from your computer to a... say... memorex tape (the type you used to use in your walkman) the serial number will not be stored on it. Think about it... even if you didn't have the tape recorder hooked up to your computer, you could set up the tape recorder next to the speakers (the quality would be pretty crappy, but could be cleaned up). How is the digital serial number going to magically jump from the computer to the tape? Across the air?
Market Data 
Markets 
AI
