Copyright law is often associated with quintessentially creative works — novels, films, music, and visual art. Yet many of the most commercially significant works in today’s economy occupy a less celebrated corner of copyright doctrine. These works contain sufficient originality to qualify for copyright protection, but only to a limited extent. As a result, they receive what courts have termed “thin” copyright protection.
The doctrine recognizes a fundamental principle of copyright law: protection extends only to original expression, not to the facts, ideas, systems, methods, or other unprotectable elements that often comprise much of a work’s value. Consequently, where creativity is constrained or originality is modest, the scope of protection narrows, making infringement substantially more difficult to establish.
The concept finds its roots in the Supreme Court’s landmark decision in Feist Publications, Inc. v. Rural Telephone Service Co., which reaffirmed that originality is the constitutional touchstone of copyright protection and that facts themselves are not copyrightable. Thin copyright thus exists at the intersection of creativity and limitation — a doctrinal middle ground between complete nonprotection and the broader safeguards afforded to highly expressive works. Understanding where that line is drawn is increasingly important, as some of the most valuable modern assets derive their worth not from extensive creative expression, but from the careful selection, arrangement, or presentation of otherwise unprotectable material.
Public Domain Texts and the Limits of Copyright Ownership
Religious texts provide one of the clearest illustrations of the thin copyright doctrine. The Torah, for example, resides in the public domain. Its ancient text may be copied, reproduced, and distributed freely because copyright does not protect works whose authorship predates modern copyright law. Likewise, a traditional Torah scroll is produced according to exacting religious requirements that leave little room for individual creative expression. The scribe's role is one of faithful replication rather than original authorship.
The digital age, however, has complicated this seemingly straightforward principle. Although the underlying Torah text remains free for all to use, modern publishers frequently incorporate original elements that may qualify for copyright protection. Editorial commentary, annotations, translations, formatting choices, pagination systems, digital interfaces, and search functionality can all reflect varying degrees of creative judgment.
The case law illustrates the distinction. In Shulsinger v. Grossman, a court found that corrections to accents and cantillation marks in a public-domain Torah text involved sufficient originality to merit copyright protection. Similarly, Ziegelheim v. Flohr recognized that distinctive pagination and organizational choices may constitute protectable expression. By contrast, in Torah Soft Ltd. v. Drosnin, copyright protection did not extend to functional modifications designed merely to facilitate electronic searching and retrieval, because copyright does not protect purely utilitarian features. And in Merkos L'Inyonei Chinuch v. Otsar Sifrei Lubavitch, the court recognized that an English translation was entitled to protection because translation necessarily requires numerous creative and linguistic judgments.
These cases underscore a central principle of copyright law: while the underlying public-domain text remains available for all to use, copyright may protect the original creative contributions that later authors, editors, translators, and publishers add to it. The resulting protection, however, is often narrow. Because the copyright extends only to those incremental contributions — and not to the underlying work itself — the copyright holder receives only a thin layer of protection over an otherwise unprotectable text.
Comedy, Ideas, and Expression
The same distinction appears in stand-up comedy. Comedians routinely build material from common human experiences—dating, work, family life, social awkwardness, and countless other recurring themes. Copyright law does not grant ownership over those premises. Instead, protection focuses on the specific way a comedian expresses the joke.
The difference between an idea and expression can be subtle but critical. A comedian cannot monopolize jokes about lawyers, but another performer generally cannot copy the precise wording, timing, and structure that make the original joke work.
The litigation surrounding Jeff Foxworthy’s famous “You might be a redneck if …” jokes illustrates this principle. Courts recognized that the joke format itself was unprotectable, but they also acknowledged that close paraphrasing of Foxworthy’s specific jokes could constitute infringement. Similarly, in Kaseberg v. Conaco, courts allowed claims to proceed where punchlines and wording were allegedly copied with substantial similarity.
At the opposite end of the spectrum stands Abbott and Costello’s iconic “Who’s on First?” routine. In Keeling v. Hars, because the routine was scripted, fixed, and highly developed, courts treated it as a protectable dramatic work. Verbatim copying of the routine crossed the line into infringement.
AI-Assisted Works and Human Creativity
Artificial intelligence has revived longstanding questions about what copyright actually protects. Recent decisions make clear that purely AI-generated material generally does not qualify for copyright protection because it lacks human authorship.
However, the law recognizes that humans often contribute creativity through the selection, coordination, and arrangement of AI-generated outputs. That contribution may be protectable even if the underlying AI-generated content is not.
The Copyright Office’s treatment of Zarya of the Dawn is particularly instructive. Although the AI-generated images themselves were not protected, the human author’s selection and arrangement of those images within the graphic novel qualified for copyright protection. Likewise, Thaler v. Perlmutter reinforced the principle that human authorship remains an essential prerequisite to copyright.
The result is often a form of thin copyright: protection exists, but only for the specific human contributions rather than the AI output as a whole.
From Maps to TikTok
Mapmaking provides another classic illustration of the idea-expression distinction. While geographic facts themselves are not subject to copyright protection, a cartographer's original decisions regarding the selection, arrangement, labeling, and visual presentation of those facts may qualify for protection. Courts have long distinguished between uncopyrightable factual information and the creative manner in which that information is organized and displayed. Even the well-known practice of inserting fictitious “trap streets” or other deliberate inaccuracies into maps serves primarily as evidence of copying rather than as an independently protectable element of the work.
The same principles increasingly arise in disputes involving social media influencers and digital content creators. Copyright law generally does not protect a video's overall aesthetic, mood, style, color palette, or vibe. Instead, protection is typically limited to specific original expressive elements, such as scripted narration, original dialogue, distinctive camera work, creative editing choices, or unique sequencing of visual content. As a result, a creator may successfully claim infringement based on the copying of particular expressive features, but not merely because another creator adopts a similar look, feel, or trend.
TikTok dance routines present perhaps the most visible modern example of these limitations. Viral dances can generate tremendous cultural influence and commercial value, yet many consist of short sequences of commonplace movements that may not satisfy the originality requirements of copyright law. Litigation arising from the use of popular dance moves in video games such as Fortnite underscored this challenge, with courts generally concluding that individual dance moves and brief choreographic sequences fall short of the level of creative expression necessary for copyright protection.
Nevertheless, the absence of robust copyright protection does not necessarily prevent creators from capitalizing on their work. Market forces often fill the gap where intellectual property law provides limited remedies. Brands regularly enter into endorsement, licensing, and promotional partnerships with creators whose dances, trends, or online personas achieve widespread recognition. As a result, even where copyright protection is uncertain or unavailable, creators can often derive significant economic value from the popularity and cultural impact of their content.
The Continuing Importance of Thin Copyright
Copyright law does not protect everything that is valuable, popular, or influential. Rather, it protects original expression while leaving ideas, facts, methods, and other foundational elements available for others to build upon. That line is not always easy to draw, but it is one of the most important principles in intellectual property law.
As new technologies continue to transform how creative works are produced and distributed, disputes over the scope of copyright protection will only become more common. Whether the work at issue is a religious text, a comedy routine, a software program, an AI-assisted creation, or a viral TikTok video, the same question ultimately governs: what portion of the work reflects protectable original expression? The answer defines not only the rights of the copyright owner, but also the freedom of others to create the next generation of works.