When you create a new piece of intellectual property, such as a software program or app, the copyright you register with the U.S. Copyright Office not only establishes that this is, in fact, your creation, but also protects you against infringement by others.
As Stanford University explains, however, your copyright does not protect you against all uses of your property by others. The Fair Use Doctrine allows others to copy, publish and otherwise distribute small portions of your copyrighted material in some situations.
No hard and fast definition exists for what constitutes fair use. Rather, it represents an exception to copyright infringement that infringers often use as a defense to alleged infringement. After listening to all the facts of a particular situation, courts make their decisions on a case-by-case basis.
Commentary and criticism
Fair use allows reviewers, critics, educators, researchers and others whose jobs consist of commenting on or criticizing the works of authors, composers, artists, developers, etc. to use a small portion of your work in their commentary. Nor do they need your permission to do this. This particularly applies if the person’s intent in using your copyrighted material is to educate students or the public.
Fair use likewise allows others to parody your work. In these types of alleged infringement, the defendant asserts that he or she merely imitated your work in a comic or ridiculous way so as to provide others with a “good laugh” or other similar enjoyment.
Despite the potentially far reach of the Fair Use Doctrine, under no circumstances does it allow an alleged infringer to deprive you of your material’s market, income or profits.