The New York Times has a good article on a trademark abuser (He Says He Owns the Word 'Stealth' (Actually, He Claims 'Chutzpah,' Too)).

Over the last few years, Leo Stoller has written dozens of letters to companies and organizations and individuals stating that he owns the trademark to "stealth." He has threatened to sue people who have used the word without his permission. In some cases, he has offered to drop objections in exchange for thousands of dollars. And in a few of those instances, people or companies have paid up....

"We're entitled to own it with all goods and services," he said. "We were there first."...

Mr. Stoller has taken his claims to federal court - with unusual frequency, in at least one judge's view. In one case in 1999, United States District Judge Joan B. Gottschall in Chicago noted in a decision against Mr. Stoller and S. Industries that the company had appeared before the court 33 times from 1995 to 1997.