Copyright helps to preserve the institutions of communication that make democracy possible. But copyright can also be used to limit open, democratic debate and the sort of critical analysis that makes it possible for a democracy to reflect on itself.
There's an interesting column today in the New York Times by Lawrence Lessig about copyright and politics. Lessig is not an anti-copyright fundamentalist. The column makes interesting reading.
The copyright and fair use problem as it affects critical social reflection is addressed on the blogs Bag News Notes and Notes on Politics, Theory, and Photography -- there are links to both on this page; the discussions of fair use are posted in the sidebars of these sites.