Home Box Office (HBO) (plaintiff) and Showtime (defendant) competed in the subscription television industry. Showtime began an advertising campaign based around the slogan “SHOWTIME & HBO. It’s Not Either/Or Anymore.” Showtime sought to inform consumers that it had access to movies that HBO did not, and thus customers should subscribe to both. Thus, Showtime claimed its ad campaign actually sought to differentiate its service from that of HBO’s. Some of its advertising, but not all, contained disclaimers clarifying that HBO and Showtime were separate companies. HBO filed suit for trademark infringement. The district court granted HBO an injunction, enjoining any advertising using the slogan that did not contain a disclaimer. The court, however, permitted the slogan in any advertising that did contain a disclaimer. HBO appealed.