Meanwhile, Google filed a neutral brief (it was not in favor of Prince, as has been previously reported) objecting to the specific language used by the district court judge finding in favor of Cariou. The document written by the Google legal team says that the opinion "diverges in dangerous ways from the mainstream of fair use analysis." Specifically, it refers to two passages from the original Prince v. Cariou opinion, which notes that "all of the precedent that this Court can identify imposes a requirement that the new work in some way comment on, relate to the historical context of, or critically refer back to the original works," and goes on to say that "Prince's Paintings are transformative only to the extent that they comment on [Cariou's] photos."

This particular argument, Google says, is "simply not the law." The opinion as it stands imposes a very narrow definition of fair use, which requires that a new work that uses content from a copyrighted work be "transformative." Specifically, it has to transform the old work by commenting on or criticizing the original work. If this were the law, Google would have a big problem. The company uses a lot of copyrighted work (notably, a huge chunk of the Internet) without transforming it at all. In order to show webpages that appear on its search page, it basically trolls the Web, copying all the pages it finds in order to index the web's content. When it does that, it copies without comment or criticism — if it did, the search function wouldn't be helpful. Thus far, the courts have ruled in favor of Google and similar defendants, saying that the way search functions index the web qualifies as fair use because "large-scale copying of works in digital form was required to achieve a socially useful goal."

However, the distric court in the Cariou case defined a much, much narrower scope for fair use that, if it stands up on appeal, might hand every every indexed Web site cause for a copyright infringement lawsuit. Even though the search function is largely a useful digital tool that brings traffic to Web sites and its unlikely that anything short of a Supreme Court ruling could actually bring it down, the language of this decision does leave Google vulnerable to lawsuits from any old Joe with a copyrighted Web page and an opportunistic attitude. The probability that Google would actually be faced with millions of lawsuits is fairly slim — after all, Google's search index is helpful to most sites and brings in a fair amount of traffic. However, it's not negligible, and the requirement that a work must be transformative in order to be fair use puts Google — and most of the Internet — in a very precarious position indeed.