David Letterman and John Stamos aren’t the only ones. The Wall Street Journal reports a boom in blackmail and extortion, which many blame on the economic downturn. Private investigators find themselves overwhelmed with high-end clients terrified about personal secrets being revealed. His clients are primarily men hiding extramarital affairs, often being extorted with digital evidence of their dalliances. In one cut-and-dry case, a 55-year-old Connecticut man said women he met on a Web site catering to wealthy men in want of girlfriends threatened to tell his wife he was a member. During the last recession, federal extortion prosecutions spiked by some 30 percent. Though the statistics aren’t yet out for this recession, the Journal's sources say that a second extortion crime wave is under way.