When a consumer stops paying a bill, creditors often try to collect on their own for a few months. In many instances, the creditor hires another company to collect the debt. In other cases, they may dispose of the debt by selling it to a debt buyer for a steep discount.

Image Steven Katz, a former bill collector, says debtors can “use the laws as they are on the books as both a shield and a sword” against unscrupulous collection efforts. Credit... Samantha Sais for The New York Times

Debt collectors and debt buyers are the targets of litigious consumers, since the debt collection law primarily applies to third-party collectors.

Peter Barry, a Minneapolis trial lawyer, is so bullish on the future of debt collection litigation that he holds several “boot camps” each year to share his secrets with other lawyers who want in on the action. If the debtor wins a court case under the act, the debt collector must pay the lawyer’s fees.

The next boot camp is being held in early May in San Francisco, at a cost of $2,495 a person for two and a half days of instruction.

“I can’t sue every illegal debt collector in America, although I’d like to try,” Mr. Barry said.

Mr. Katz can also claim some credit for the increase in lawsuits. For six years, he has run a free Web site called Debtorboards.com, where people share tips on topics like keeping a paper trail and recording calls from collectors.

He said the site received two million hits in 2009, a 60 percent increase over the previous year.

“Debtorboards is geared to help people use the laws as they are on the books as both a shield and a sword,” said Mr. Katz, who says he has won $36,000 from his own litigation against collection agencies. (Since many of the settlements are confidential, it is difficult to prove the claims of Mr. Katz and others).

Of course, debt collectors are hardly pleased with the litigation trend.

Rozanne M. Andersen, chief executive of ACA International, a trade association for the debt collection industry, said she was “extremely concerned” about the increase in lawsuits, which she said cost her industry hundreds of millions of dollars a year. She said much of the increase was the result of ambiguous language in the Fair Debt Collection Act.