From Letterman's monologue describing sexual liaisons with staffers to Travolta's emotional testimony about his son's death, celebrities confronted information and allegations that others offered to keep secret, for a price.
And those are just the cases that came to light. Experts say extortion is a constant threat to those in the spotlight.
"For every one you hear about, there's probably 10 you don't," said Mark Geragos, a Los Angeles attorney who's handled numerous criminal and civil matters involving famous clients. "Just within the last three weeks, I've had two I've put to bed without anybody hearing about (it) that would have been household names."
In the Travolta, Letterman and Crawford cases, the alleged attempts to get money backfired and resulted in criminal cases being filed. The past year's crop of alleged victims joins many other entertainers who have had to contend with extortion, including Elvis Presley, Bill Cosby, Michael Jackson, and Tom Cruise, to name a few.
Extortion statistics are difficult to come by. It can be charged under several different statutes at both the state and federal level. While some say anecdotal evidence shows extortion is becoming a more common tactic, the targeting of celebrities has been a constant problem.
"I don't think it's more prevalent," said Marty Singer, a Los Angeles entertainment attorney for more than 30 years. "In the last 10 years I don't think I've handled any more extortion cases than the previous 10 years."
Singer said he handles about one celebrity extortion case a month. He said the main difference now is that the financial demands are higher, and the people attempting to trade on the info are more aggressive. "It's sometimes the cost of doing business," he said.
Celebrity attorneys say that extortion attempts against their clients often involve information that isn't true. In some instances it doesn't matter if its release will hurt the entertainer's reputation.
"It's a different ballgame for celebrities," said David Shapiro, a former FBI agent and associate professor at John Jay College of Criminal Justice in New York. "Celebrities are especially vulnerable because they have an image."
A lot depends on the celebrity's reputation and how they want to handle the demands. "I have clients who couldn't care less if a sex tape comes out because they think it's going to make them more famous," Geragos said.
He said sometimes a person "overvalues" the item or information they're using to try to extort a celebrity. Actor John Stamos apparently felt that way when a Michigan couple threatened to sell pictures of him for $680,000. They have been arrested and face a federal extortion charge.
"At the conclusion of the investigation and hearing, the photos will be available and the public will be able to see that the photos are simply John posing with fans," Stamos spokesman Matt Polk said after the arrests earlier this month.
Alerting authorities is how the public learns about most celebrity extortion attempts. Nowadays, they almost always become big news.
Travolta's case became international news when Bahamian authorities arrested two people accused of trying to sell the actor an innocuous medical treatment document after his son's death. Travolta gave emotional testimony in the case against the suspects, a paramedic and former Bahamas senator, but the case ended in a mistrial. The actor has said he will testify again.
Letterman chose to announce the case involving him on his late-night talk show after an arrest was made. An attorney for Robert J. "Joe" Halderman, the man accused of trying to blackmail Letterman, has denied any wrongdoing by his client, saying he was merely shopping a screenplay.
"Evidence of celebrity misdeeds has a significant fair market value," Halderman's lawyer Gerald Shargel wrote. "... Evidence of such misdeeds is routinely suppressed through private business arrangement."
Shapiro said extortion attempts can involve a lot of gray area. "Not to condone extortion, but at what point is extortion merely somebody exploiting somebody else's vulnerability," he said.
Shapiro said extortion's secretive nature also makes it a relatively low-risk crime.
"In terms of crimes, if you're going to gamble, it's certainly one of those that the rewards greatly exceed the risks," Shapiro said.
The publicity inherent with involving authorities in extortion cases is a tough call, Geragos and Singer said.
"You can't really control it," Geragos said. "You have to relive it."
Geragos, who represented Jackson shortly after his arrest on child molestation charges, said finding out someone is trying to sell secretly obtained information can provoke strong reactions. Geragos and Jackson were secretly videotaped on a private plane, and the attorney won a $20 million judgment against the plane's operator last year as a result.
"It's a sickening feeling and an outrageous feeling," Geragos said.
"When clients come, I tell them, 'I've been there, I can relate to you,"' he said.