US Trademark Law/Infringement
Confusion is one of the main grounds for a trademark infringement claim. It can take many forms, but the basic inquiry generally involves the same questions:
- How strong is the mark being defended?
- How similar are the products in question?
- How similar are the marks in question?
- Have consumers actually been confused?
- Which marketing channels have been used?
- How likely is the consumer to exercise care when purchasing the products in question?
- What was the defendant's intent in selecting the mark?
- How likely are the product lines to expand?
See AMF v. Sleekcraft Boats, 599 F.2d 341 (9th Cir. 1979). Different circuit courts use slightly different tests in determining likelihood of confusion.
Infringement by confusion can involve:
- Confusion between related products. If one product is offered under a mark similar or identical to another, and the products would be confused by the buying public if sold under the same mark, trademark infringement can be found. Examples from actual infringement cases include Slickcraft and Sleekcraft boats, Bonamine and Dramamine medications, Pledge and Promise cleaners, and Duron and Durox paints.
- Confusion as to source. Confusion can also be found when the same or similar mark is applied to different types of goods. One early case, involving Borden milk and Borden ice cream, was deemed to be non-infringing in 1912; in more recent years, such cases have routinely led to findings of infringement.
- Confusion as to sponsorship. Even where consumers are unlikely to be confused as to source, they may be confused as to sponsorship. Team logo merchandise is a common example; consumers may expect that they are supporting the New York Yankees by purchasing a Yankees cap.
- Initial interest confusion. Sometimes, famous marks are used to lure consumers to different businesses. "Cybersquatting" by registering a well-known trademark as a domain name is one well-known example. Another is the use of meta tags to fool search engines: a little-known adult Web site may attempt to attract visitors by showing up in web searches for more well-known adult entertainment franchises. Both activities can be considered trademark infringement by confusion.
- Post-sale confusion. Post-sale confusion is often used to find infringement in counterfeit goods, such as fake watches and handbags. While the purchaser is likely to understand that they are buying a counterfeit product, the aim is to confuse others into thinking the product comes from a different source.
- Reverse confusion. Although confusion cases generally involve a little-known business using a well-known mark, confusion can also be found when a well-known business uses a little-known mark.
Trademark infringement can also be found in the absence of any confusion at all. Many trademarks are deemed to have a distinctive quality, and any third-party use that diminishes this distinctiveness is considered to be dilution, which is an independent cause of action from traditional infringement. Traditional types of distinction include blurring, in which the diluter lessens the ability of the mark to uniquely identify one source of goods or services, and tarnishment, in which the diluter associates the mark with scandalous or obscene material, thus attacking the good character of the mark or its owner.
The textbook case of dilution is Eastman Photographic Materials v. Kodak Cycle, 15 R.P.C. 105 (Eng. 1898), in which the maker of Kodak cameras brought suit against a company producing Kodak bicycles. There was little chance of cameras being confused with bicycles: the risk was removing the Kodak name's association with cameras.
The Federal Trademark Dilution Act of 1995 added a dilution statute to the Lanham Act. Dilution can be found whenever a "famous mark" is used by another, "if such use begins after the mark has become famous and causes dilution of the distinctive quality of the mark." 15 U.S.C. 1125(c). However, a recent law has made significant changes to the Federal dilution statute. 
Trademark law has a contributory infringement doctrine similar to those under patent law and copyright law. Unlike its sister doctrines, however, contributory infringement of trademarks is not a very well-developed doctrine. It has come up in a few contexts, including cybersquatting liability and liability for landlords whose tenants sell counterfeit goods.
Defenses to infringement
Many trademarks have been invalidated because they have lapsed from fanciful, arbitrary, suggestive or descriptive status to generic status. Genericide is a defense to trademark infringement: the use of a trademark that has become generic over time is not infringement. Examples include:
- aspirin; Bayer Co. v. United Drug Co., 272 F. 505 (S.D.N.Y. 1921).
- cellophane; DuPont Cellophane Co. v. Waxed Products Co., 85 F.2d 75 (2d Cir. 1936).
- shredded wheat; Kellogg Co. v. National Biscuit Co., 305 U.S. 111 (1938).
- thermos; King-Seeley Thermos Co. v. Aladdin Industries, 321 F.2d 577 (2d Cir. 1973).
- Murphy bed; Murphy Bed Door Co. v. Interior Sleep Systems, 874 F.2d 95 (2d Cir. 1989).
- Pilates; Pilates, Inc. v. Current Concepts, Inc., 120 F.Supp 2d 286 (S.D.N.Y. 2000).
- Pilates Studio; Pilates Method Alliance, Inc. v. Pilates, Inc., Opposition No. 91154584 (TTAB 2004).
Many companies, notably Xerox, Jeep and Lego, have active campaigns to avoid the genericide of their trademarks: they insist that their marks be used as adjectives, not nouns, so as to avoid their trademarks becoming common terms for copying machines and interlocking blocks respectively. Xerox regularly engages in corrective advertising. In the late 1980's, Jeep after being acquired by Chrysler convinced the automobile industry to adopt the term SUV for 4-wheel drive vehicles, and has since engaged in a continuous advertising that "There is only one Jeep" to reinforce the JEEP brand.
The original Trade-Mark Cases invalidated Congress's first trademark statute on the grounds that trademark authority could not be based on the patent and copyright clause of the Constitution. There is still a sharp divide between patent and trademark law, illustrated by the doctrine that functional marks cannot be protected as trademarks. As stated above, functionality is most common when defending claims for infringement of trade dress and product configuration.
Under the Lanham Act as amended in 1994, a mark is deemed "abandoned" "when its use has been discontinued with intent not to resume such use." Nonuse for three consecutive years is considered prima facie evidence of abandonment. 15 U.S.C. § 1127.
Some famous trademarks have been preserved through minor use by other companies. US Airways, for instance, preserves the trademarks of well-known but defunct Piedmont Airlines and PSA by operating some of its commuter flights under those names, and Chevron maintains the Standard Oil trademark by operating a small number of its filling stations under the Standard name.
Use of a mark is only infringing if the mark is used as a mark. For instance, mentioning a mark in an article is generally not infringement. Using a mark as the basis of a song is generally not infringement ("Barbie Girl"; see Mattel v. MCA Records, 296 F.3d 894 (9th Cir. 2002)). Likewise, mentioning a mark in the title of a work, as in The Lexus and the Olive Tree or The Devil Wears Prada, is generally not infringement. However, using Star Trek in the title of an unauthorized book about Star Trek would likely infringe the mark, since the mark is used on other books authorized by its holder.