It would seem as though MP3s are a miracle;
this is not true for everyone involved, especially the corporate giants responsible
for the offline sale of music.

The fight has best been fought be the RIAA, which is a group that represents the
five major record label distributors - WEA, UNI, BMG, Sony, and Capitol.
You can read all about it here:

Mainly, the RIAA just wants to make sure artists are protected if they don't actually want
their music distributed through MP3.com or like sites.

In order to help protect artists' rights, the RIAA has created the SDML (Secure Digital Music Initiative).
You can check out what they do here:

The SDMI is trying to create a framework for technological community (this doesn't just include music)
for which to deal with the online distribution of copyrighted material.

So what is actually being done to protect copyrighted music online?
One thing is a watermark, which is almost like a watermark on a personal check.
It would not be audible to the human ear, but could be picked up with equipment
and would identify songs.
Read about it here:

One thing a lot of the big-wigs are worried about is the manipulation of songs online.
For example, after the death of Tupac Shakur, one of his previously unreleased songs got out
and another want-to-be rapper forged a "duet," and sold it as his own.

While MP3s may have many positive qualities, there are certain destructive aspects that
could be responsible for hurting a lot of people if not dealt with properly.