Start Here - Practically Indisputable Economics:
In a competitive market, where products can be easily COPIED, prices get pushed down to marginal cost; thus practically eliminating the ability to generate a profit; therefore the solution is to create products or features that can't be simply REPLICATED.

And Then The Music Industry Said:
In a competitive market, where products can be easily COPIED, prices get pushed down to marginal cost; thus practically eliminating the ability to generate a profit; therefore the solution is to stop people from REPLICATING our products.

But, Someone Put The Wrong Statement In The Play Book.  It Should Have Read:
In a competitive market, where products can be easily SUBSTITUTED, prices get pushed down to marginal cost; thus practically eliminating the ability to generate a profit; therefore the solution is... (a post covering this is in the works).

Common Sense Says - Rule Out This Option:
In a competitive market, where products can be easily SUBSTITUTED, prices get pushed down to marginal cost; thus practically eliminating the ability to generate a profit; therefore the solution is to stop people from SUBSTITUTING our products.

Substitution Is a Bigger Problem Than Replication
At this point in time, given the adoption of MP3 players (including cell phones), broadband Internet, Internet everywhere, video game consoles and the pending media recommendation tsunami - substitution of one song instead of another is a far bigger challenge than replication; that is, if you don't have the right strategy... 

Continue to the follow up post on substitution.