CDs are digital storage media. Owners of a CD burner - now included in most PCs - can burn their own CDs from (non-encrypted) audio files. The same works vice versa, thus allowing CDs to be copied without loss of quality. Fine for gratis music. The CD technology, particularly the AudioCD format, are not the best technology available nowadays, but will still be around for quite a while.

The industry is currently experimenting with methods to make copying more difficult, and to ensure payment. The most successful idea hitherto is to customize the data so that they can only be used on a single individual device, whose interiors are accessible to the provider rather than the owner. Inevitably, this renders the concept of "possession" more abstract than it used to be. Methods will be refined in the future, but attaching text and photos is no problem right now.

Summary: economics is the problem.