The files which are purchased from the online store are in AAA format (with encryption). This encryption is based on Digital Rights Management (DRM) system. The files can be played by iPod (unlimited in number) and up to 5 computers (authorized).

When you burn the file onto a CD, Digital Rights Management is removed. The quality also goes down.

iPods are unable to play music files which are encrypted with other DRM technologies like RealNetworks' Helix-DRM or Microsoft's protected WMA.

Hardware: initially, iPod was only capable of connecting to the computer for updating songs and then recharging the battery though FireWire. Charging was also possible by small power adapter which were shipped free with the first generation iPods.

The dock connector which is the standard now was added in the third generation on April, 2003. This allowed the users to use USB or FireWire for transferring data. However it was still not possible to charge the device by USB. It also had no USB cable.

However FireWire ports are not present in most of the PC's. This opened the way for Windows. The Window users were required to plug the FireWire cable into the adapter.

Data, power back and sound can also be transferred to iPod accessories through the dock connector. These accessories actually turned out to be highly profitable for Griffin and Belkin. iPod biggest strength still lies in its connecting devices.

The fourth generation iPod capabilities can also be recharged with USB. Apple now ships USB cables with iPod's rather than FireWire. USB 1.1 was shipped with Macs before 2004. The transfer rate of this USB was 11 Mbit per second. This was quite less as compared to USB 2's speed of 480 and FireWire's 400.

However, these transfer rates are rarely achieved. USB 1.1 is quite slow compared to the other two. People may find it ineffective for transferring music to an iPod (40 GB iPod). iPod is not much dependent on FireWire as it used to be earlier.