Monica Lewinsky joined Twitter this morning.

In her Twitter bio Lewinsky, former White House intern and mistress of President Bill Clinton, describes herself as "social activist. public speaker. contributor to vanity fair. knitter of things without sleeves."

Lewinsky's first tweet came shortly before she spoke at Forbes' 30 Under 30 summit in Philadelphia, where she told the crowd she wanted to launch a "cultural revolution" against online harassment. According to Forbes:

"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'."

Her account quickly attracted thousands of followers and lots of comments. Predictably, not all of them nice.