The main operative logic and language of the court's decision:
The PTO’s principal concern is that trademark protection for a term like “Booking.com” would hinder competitors.
But the PTO does not assert that others seeking to offer online hotel-reservation services need to call their services
“Booking.com.” Rather, the PTO fears that trademark protection for “Booking.com” could exclude or inhibit competitors from using the term “booking” or adopting domain names like “ebooking.com” or “hotel-booking.com.” Brief for Petitioners 27–28. The PTO’s objection, therefore, is not to exclusive use of “Booking.com” as a mark, but to undue control over similar language, i.e., “booking,” that others should remain free to use. That concern attends any descriptive mark. Responsive to it, trademark law hems in the scope of such marks short of denying trademark protection altogether. Notably, a competitor’s use does not infringe a mark unless it is likely to confuse consumers. See §§1114(1), 1125(a)(1)(A); 4 McCarthy §23:1.50 (collecting state law). In assessing the likelihood of confusion, courts consider the mark’s distinctiveness: “The weaker a mark, the fewer are the junior uses that will trigger a likelihood of consumer confusion.” 2 id., §11:76. When a mark incorporates generic or highly descriptive components, consumers are less likely to think that other uses of the common element emanate from the
mark’s owner. Ibid. Similarly, “in a ‘crowded’ field of lookalike marks” (e.g., hotel names including the word “grand”),
consumers “may have learned to carefully pick out” one mark from another. Id., §11:85. And even where some consumer confusion exists, the doctrine known as classic fair use, see id., §11:45, protects from liability anyone who uses a descriptive term, “fairly and in good faith” and “otherwise than as a mark,” merely to describe her own goods. 15 U. S. C. §1115(b)(4); see KP Permanent Make-Up, Inc. v. Lasting Impression I, Inc., 543 U. S. 111, 122–123 (2004).
These doctrines guard against the anticompetitive effects the PTO identifies, ensuring that registration of
“Booking.com” would not yield its holder a monopoly on the term “booking.” Booking.com concedes that “Booking.com” would be a “weak” mark. Tr. of Oral Arg. 66. See also id., at 42–43, 55. The mark is descriptive, Booking.com recognizes, making it “harder . . . to show a likelihood of confusion.” Id., at 43. Furthermore, because its mark is one of many “similarly worded marks,” Booking.com accepts that close variations are unlikely to infringe. Id., at 66. And Booking.com acknowledges that federal registration of “Booking.com” would not prevent competitors from using the word “booking” to describe their own services. Id., at 55.