Former White House intern Monica Lewinsky, who grabbed headlines as mistress of former US President Bill Clinton, on Sunday broke a decade-long silence to announce her campaign to end cyberbullying.

In her first ever public address, she revealed her plan to launch a "cultural revolution" against the sort of online harassment which she was subjected to in the late 1990s.

"I was Patient Zero," said Lewinsky, now 41, to an auditorium full of 1,000-plus high-achieving millennials at Forbes' inaugural 30 Under 30 summit in Philadelphia. "The first person to have their reputation completely destroyed worldwide via the Internet."

"There was no Facebook, Twitter or Instagram back then," she said. "But there were gossip, news and entertainment websites replete with comment sections and emails which could be forwarded. Of course, it was all done on the excruciatingly slow dial up. Yet around the world this story went. A viral phenomenon that, you could argue, was the first moment of truly "social media"."

Lewinsky said that her life since the sex scandal that broke out in 1998 and resulted in Clinton's impeachment has been marred by a deep sense of shame and even suicidal thoughts.

"Staring at the computer screen, I spent the day shouting: "Oh my god! and "I can't believe they put that in? or "That's so out of context,"she said. "And those were the only thoughts that interrupted a relentless mantra in my head: "I want to die."

Following the Clinton saga, Lewinsky tried to capitalize on her notoriety, first designing handbags and then hosting a reality dating show. She moved to the UK, where she attended the London School of Economics and got a master's degree in social psychology.