Lossy formats selectively discard sounds human ear can't hear to make file smaller. But each format removes slightly different sounds. For example, converting a track using a WMA to mp3 converter is now missing sounds that both codecs have deleted.

There are other ways to remove DRM and convert WMA to mp3, but they require numerous steps and more software - and they're not for technically challenged. Free WMA to mp3 conversion software and detailed instructions are available on Internet.

Until 1989 traditional digital music format was WAV file. Basically a digital conversion of analog wave-form signal, it provided high quality sound recordings. But a 4 to 5 minute song consumed up to 50MB of memory. By selectively discarding sounds inaudible to human ear, mp3 format was able to store same song in less than 5MB. Some formats like WMA and OGG can cut that to around 2MB with even higher quality sound.

With advent of flash memory and tiny hard drives known as micro-drives, by late 1990's manufacturers began introducing small digital music players. And today some portable music players can store thousands of songs, photos and other data in a portable player about size of a deck of cards!