There are specific situations in which using another party's trademark in advertising can be considered fair use, serving as an affirmative defense against trademark infringement. One such circumstance is comparative advertising, which falls under the category of Nominative Use. This occurs when one party utilizes another party's mark to refer to the mark owner or their goods and services. The use of the trademark must be necessary for identification purposes and should not imply or suggest any form of sponsorship, endorsement, or affiliation by the mark owner. In essence, if a third party uses a mark in comparative advertising without confusing or misleading consumers, and only employs as much of the mark as necessary for identification (for instance, using the words but not the same font or graphics), it will be considered fair use. Another example of Nominative Use is when a distributor or retailer describes the goods they offer for sale.

The second circumstance where using another's trademark in advertising is permissible under the doctrine of fair use is when the term is used in a descriptive manner. This usage must be in good faith and primarily represent the term's ordinary meaning. The term or trademark should be employed in a way that does not function as a trademark and does not cause consumer confusion.

Another area of advertising that often raises controversy is the use of trademarks as keywords. Keywords are terms used by individuals conducting online searches to find information related to their query. Keyword advertising occurs when an advertiser pays a search engine to display their advertisement in response to a search engine query that includes selected keywords.

For instance, the "something more" could involve using the third party's trademark in the text of the advertisement that appears in response to the keyword-triggered search. It's important to note that the advertisement is placed by a party other than the trademark owner and utilizes another's trademark without authorization. If the trademark is used in a manner likely to cause confusion, deception, mistake, or implies sponsorship, endorsement, or affiliation between the trademark owner and the advertiser, the majority of courts would prohibit such usage and consider it infringement. In such a scenario, the trademark owner should consult with trademark counsel and consider sending a Cease & Desist Demand to the advertiser.