Before you use someone else's work without permission,consider ALL 4 FACTORS (Title 17 U.S.C. Sec. 107):

1. Nature of the copyrighted work
2. Amount, substantiality
3. Effect

1. Nature of the copyrighted work

• Character of the work
  
  • for example, fact or fiction
    
• Worthy of (extensive) protection?

2. Amount and substantiality© Myth: Copying just a little bit is OK.

• Use only what is necessary
  
• Quantity and quality in relation to the whole work
  
  • President Gerald Ford's memoirs: Harper & Row, Publishers, Inc. (Time magazine) v. Nation Enterprises, 1985
    http://www.publaw.com/fairuse.html

3. Effect

• Harm to potential market or value of a work after a portion has been used separately from the whole
  
  • (Ford’s memoirs)
    
  • © Myths
    
    • Attribution is as good as permission.
      
    • It's free advertising.

original by Brad Templeton
http://www.templetons.com/brad/copymyths.html