via: http://digital-scholarship.org/digitalkoans/2009/07/23/fair-use-evaluator-and-exceptions-for-instructors-etool-released/

the flexibility that fair use offers versus the certainty offered by more specific exceptions for research and teaching found in the copyright laws of most other countries

good intro to copyright

Judicial placement of the burden with fair users represents an attempt to foster expression by safeguarding copyright. The attempt has failed miserably. The burden represents heavy-handed patrolling in the marketplace of ideas. Trying to punish those who steal, courts are punishing those who share. They have turned an open emporium of exchange into a highbrow boutique for the wealthy. It is therefore time to construe fair use as it was originally intended—a doctrine that defines the scope of copyright‘s rights. It is time to restore the burden of proof to plaintiffs. It is time to return to the traditional contours of copyright that will cultivate creativity.