The Walt Disney Company has been a significant driver of extended copyright terms. Under current law, Disney's original Steamboat Willie version of Mickey Mouse (1928) entered the public domain in 2024, but subsequent iterations remain protected.

Not every expression of an idea may be copyright protected; copyright doesn't protect:

Some items on the above list, such as product names, may be afforded protection under trademark law.

Fair use

Even when a work is protected under copyright law, the law defines a category of exceptions. In those cases, copies of works may be used even when the copyright holder has otherwise restricted use.

Fair use, known in some other international jurisdictions as fair dealing, is the judicial doctrine that permits the use of copyrighted materials when the purpose serves the public interest.

The most common fair uses for copyrighted materials include the following:

Conceptually, fair use is a refinement of the basic balance copyright strikes between author and civil interests.

It is important to note, though, that what counts as fair use is generally not well delineated in copyright laws around the world. In the U.S., the law lists four basic guidelines that courts may use in lawsuits where infringement is alleged:

In the world of popular music, the boundaries of fair use have been tested as a result of the use of samples, or short snippets of copyright-protected sound recordings in new works. Clear precedents have not been established because court decisions have taken unpredictable turns.

A 2005 decision in the 6th District Court in the U.S. held that copying even as few as three consecutive notes could constitute infringement. Other cases have revolved around whether permissions must be obtained for portions of a work that are sampled, for the underlying song or both. Commercial musicians can buy clearances to sample works, meaning that whether that sampling could be allowed under fair use provisions is simply not tested.

Copyleft

An interesting exception of sorts to copyright is a concept originally championed by Richard Stallman and the Free Software Foundation, which created copyleft as a means of effectively stripping most copyright restrictions from a work to allow free use, including copying of the material, while retaining control over how the material is shared.

Under the copyleft, derivative works created using that original work must also be given copyleft protection. More broadly, this approach is known as free licensing and is considered a form of open source licensing.

Material published under open source licenses may be freely copied, modified, shared and distributed as long as the original license is applied to the distributed material. When used for publishing software, the copyleft license also requires that source code be included or made available when modified software is published.

Creative Commons

In 2001, Creative Commons, a nonprofit organization, was created to facilitate several kinds of legal sharing so that works could be freely reused but in contexts that are controlled by the copyright holder. Works covered under Creative Commons licenses are aggregated on the organization's website.