“Cybersquatting,” the practice of maliciously snapping up a Web site with someone else’s trademark in its domain name, is illegal in the United States. It is also an easy way to make money; a cybersquatter can impersonate the trademark’s owner, sell ad space to the victim’s competitors, or extort a payment in return for turning over the Web site.

A recent report from MarkMonitor, a company that sells domain names to large companies and protects them from online misuse of their brands, suggests the practice is increasingly popular in the United States — despite laws that allow trademark holders to sue. Over 2008, MarkMonitor tracked an 18 percent rise in incidence of cybersquatting, which it calculated by examining every new domain name created, checking for a trademark in the URL, and then seeing whether the trademark’s owner also owned the Web site.