In determining whether to apply fair use to an infringement, the courts look at four factors set out in the statute (although even the statute itself says that these factors are “non-exclusive”–meaning that a judge can take other, similar factors into account as well):
1. The purpose and character of the use, including whether such use is of a commercial nature or is for nonprofit educational purposes
2. The nature of the copyrighted work
3. The amount and substantiality of the portion used in relation to the copyrighted work as a whole
