In an emotional address at Forbes' inaugural Under 30 summit in Philadelphia that recalled the 1998 sex scandal with Clinton, the 41-year-old brunette announced a campaign to end online bullying.
Lewinsky told a packed auditorium that she was "the first person to have their reputation completely destroyed worldwide via the Internet."
"I was Patient Zero," she said.
"There was no Facebook, Twitter or Instagram back then.
"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'."
She spoke of her shame and depression and of harboring suicidal thoughts after news of the 1998 sex scandal broke.
"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.'"
She said she was motivated to campaign against cyber-bullying by the 2010 suicide of an 18-year-old New Jersey freshman who was haunted online after being secretly filmed kissing another man.
"Having survived myself, what I want to do now is help other victims of the shame game survive, too," she said. "I want to put my suffering to good use and give purpose to my past."
Lewinsky also joined Twitter, describing herself on her @MonicaLewinsky profile as a social activist, public speaker, contributor to Vanity Fair magazine and a "knitter of things without sleeves."
Within hours she racked up more than 18,000 followers for an account verified by the microblogging service.
Her first tweet was "#HereWeGo" and her second said she was "excited (and nervous) to speak" at the Forbes Under 30 Summit.
Nobel peace laureate Malala Yousafzai is scheduled to speak at the same event on Tuesday.
Earlier this year, Lewinsky broke her silence about her affair with Clinton, in a piece for Vanity Fair.
"I am determined to have a different ending to my story. I've decided, finally, to stick my head above the parapet so that I can take back my narrative and give a purpose to my past," she wrote.
After news of the affair broke, Clinton was impeached by the House of Representatives in December 1998 but was acquitted by the Senate.
His wife Hillary, a former secretary of state widely tipped to run for president in 2016, says she has "moved on" from the scandal.
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