Actually, from my understanding of the case law that defines "Fair use," there is no word limit on what constitutes "fair use." If an article is 65 words long, and you copy the entire thing, that is not fair use (unless you're doing so for educational or research purposes). Without getting technical, there are a number of factors a court would look at to determine whether the use is "fair" or not. Percentage copied (usually less than 10%), is one of those factors.

As mollymcn, there very well may be appropriate exceptions for educational or research purposes here, but we drew up our guidelines to strike an easy balance between what is easy for others to understand and to set a guideline that is readily followed.

DocJohn