But pranks can go wrong.

Back in 2008, the BBC apologized to actor Andrew Sachs after two radio presenters -- Russell Brand and Jonathan Ross -- left a series of messages on his phone while on-air, including offensive references to his granddaughter. The second message apologized for the first -- but also suggested Sachs might kill himself because of the content of the previous message.

The two presenters were later suspended by the BBC, and a senior executive resigned. The corporation was also fined some $225,000 by the UK media regulator and its governing trust described the episode as a "deplorable intrusion with no editorial justification."

Brand moved on -- to a career in Hollywood. Veteran publicist Max Clifford told the Daily Telegraph soon after the incident that Brand's career would not be hurt.

"He's known to be controversial and, if anything, it will make him more popular amongst his fans, who will have thought this was hilarious," Clifford told the newspaper.

As Oscar Wilde once said, "The only thing worse than being talked about is not being talked about."

Sachs was at least familiar with the public spotlight as a well-known actor and narrator. Jacintha Saldanha was not. Nor was Gretchen Molannen.

On November 30, the Tampa Bay Times published a story about Gretchen Molannen, a 39-year old woman who had a rare sexual disorder known as 'persistent genital arousal.'

The Times worked with Molannen and read her the entire story before it was published. She'd written to the newspaper thanking it for showing an interest, adding: "I just hope this will educate people that this is serious and really exists, and that other women who are suffering in silence will now have the courage to talk to a doctor about it."

The day after the story was published, Molannen killed herself. Even sympathetic coverage and subsequent offers of help could not save her.

It's unclear whether the publicity about her condition was too much to bear; she had previously attempted to take her own life.

"It's important to understand that suicide is complex," says Catherine Johnstone, chief executive of the Samaritans, a UK group that counsels people thinking of suicide.

"Although a catalyst may appear to be obvious, suicide is never the result of a single factor or event and is likely to have several interrelated causes," Johnstone said on the group's website soon after news emerged of Saldanha's death.

If adults are vulnerable to what they perceive as public humiliation, teenagers are doubly so. Tyler Clementi was an 18-year old student at Rutgers University who in 2010 was secretly filmed by his roommate having a sexual encounter with another man. A short while later he jumped to his death from a New York bridge.

Clementi was not only humiliated but his humiliation was amplified by the fact that his roommate, Dharun Ravi, shared the footage with others and tweeted about it. He was later convicted of bias intimidation and invasion of privacy and sentenced to 30 days in jail.

The case seemed to bring together many of the factors that put the vulnerable even more at risk: technology that can record and distribute private acts in a matter of minutes; the failure -- especially among many younger users of social media -- to understand the potential consequences of their postings; and the uncertain state of the law in many places.

It also highlighted an epidemic of teenage suicides in the United States -- one that has coincided with the immersion of that age group in social media and texting for hours at a stretch. Schoolyard bullying ends when recess does; cyber-bullying is 24/7 and reaches into the bedroom, the mall and the classroom.

When 15-year old Phoebe Prince killed herself in Massachusetts two years ago, another student at her school told the media: "Someone told her to go hang herself, and I don't really know who that was, but she was getting bullied by some people, because there were people talking about her and I guess she didn't like being hated."

At first glance, many of these cases bear little resemblance to that of Jacintha Saldanha. But there are common threads.

In the 21st century, personal humiliation can quickly go viral thanks to the reach and appetite of both social and mainstream media. Within hours, the minor transgressions and innocent mistakes, the private behavior and anxieties of ordinary people can reach, or seem to reach, the ends of the earth. For a few, that exposure is quickly overwhelming.