I've pointed to the Everything is a Remix series previously; it's a series of short documentaries by Kirby Ferguson, discussing how newly created work (music, movies, etc.) is influenced by existing work -- and ultimately, how our systems of copyright and patents aren't built to deal with this. (SOPA/PIPA opponents, you might want to watch this.)

In this fourth and final part of the series, Ferguson talks about artistic creation as a form of social evolution...and the history of copyright and patents. The video also covers software patents and current legislation on copyrights. Ferguson writes:

Our system of law doesn't acknowledge the derivative nature of creativity. Instead, ideas are regarded as property, as unique and original lots with distinct boundaries. But ideas aren't so tidy. They're layered, they’re interwoven, they're tangled. And when the system conflicts with the reality... the system starts to fail.

Watch it and learn up:

Watch the first three parts of the film at the Everything is a Remix site. Ferguson is also Kickstarting a new project.