The following excerpt is from Consumers Union of U.S., Inc. v. General Signal Corp., 724 F.2d 1044 (2nd Cir. 1984):
The fourth factor to consider in evaluating fair use is "the effect of the use upon the potential market for or value of the copyrighted work." 17 U.S.C. Sec. 107(4). This factor is "widely accepted to be the most important." Triangle Publications v. Knight-Ridder Newspapers, supra, 626 F.2d at 1177.
The above passage should not be considered legal advice. Reliable answers to complex legal questions require comprehensive research memos. To learn more visit www.alexi.com.