The law provides a cause of action for trademark owners if they can establish the following:

1. They own a famous mark (determined by eight factors listed in the law).
2. The defendant is making commercial use in interstate commerce of the plaintiff’s mark or trade name.
3. The defendant’s use of plaintiff’s mark occurred after the mark became famous.
4. The defendant’s use causes dilution of plaintiff’s mark by lessening the capacity of a famous mark to identify and distinguish goods or services.

The law exempts noncommercial use of trademarks. The 9th U.S. Circuit Court of Appeals explained in its 1998 decision in Bally Total Fitness Holding Corporation v. Faber that “commercial use is an essential element of any dilution claim.”

However, some courts appear to take a broad view of what constitutes commercial activity. For example, a federal district court in New York ruled in 1997 in Planned Parenthood Federation of America, Inc. v. Bucci that a radio host and anti-abortion activist who had a Web site with the domain name www.plannedparenthood.com engaged in commercial activity for several reasons. These include that fact that the radio host promoted his book on the site, solicited funds for his nonprofit political activism, and designed it to harm Planned Parenthood commercially. The court explained:

Finally, defendant’s use is commercial because of its effect on plaintiff’s activities. First, defendant has appropriated plaintiff’s mark in order to reach an audience of Internet users who want to reach plaintiff’s services and viewpoint, intercepting them and misleading them in an attempt to offer his own political message. Second, defendant’s appropriation not only provides Internet users with competing and directly opposing information, but also prevents those users from reaching plaintiff and its services and message. In that way, defendant’s use is classically competitive: he has taken plaintiff’s mark as his own in order to purvey his Internet services — his Web site — to an audience intending to access plaintiff’s services.