Legal & IP
什么是 Fair Use？
定义
Fair use is a legal doctrine in US copyright law that allows limited use of copyrighted material without permission — for purposes such as commentary, criticism, education, news reporting, and parody. Whether a use qualifies as fair use depends on a four-factor balancing test applied case by case.
The four factors courts weigh when evaluating fair use are: (1) Purpose and character of the use — commercial or transformative? Transformative works that add new meaning or expression are favored; (2) Nature of the copyrighted work — factual works receive less protection than highly creative works; (3) Amount and substantiality used — using a small portion generally favors fair use, but using the 'heart' of a work can weigh against it even if small in quantity; (4) Effect on the market — does the use substitute for or harm the market for the original? Courts generally consider this the most important factor. Fair use is determined case-by-case — there is no bright-line rule. Common misconceptions: giving credit doesn't create fair use; 'educational use' doesn't automatically qualify; and there is no percentage threshold that automatically qualifies.
为什么重要
Fair use disputes arise frequently in content creation, journalism, education, and software development. Understanding fair use helps you make informed decisions about using others' content — and responding when someone uses yours. An IP attorney can evaluate whether a specific use is defensible or whether you need a license.