Kelly Wallace is a CNN digital correspondent and editor-at-large. Read her other columns and follow her reports on Twitter.

It's been a stunning few weeks of sexual harassment allegations against extremely powerful men. Women, trying to claim some of their own power, responded in droves on social media using the hashtag #MeToo, often sharing stories of when they've been sexually harassed at work.

But sexual harassment is not limited to the workplace. Sue Scheff, author of the recently released book "Shame Nation: The Global Epidemic of Online Hate," which includes a foreword by Monica Lewinsky, says that in the digital age, sexual harassment is prevalent online, as well.

"In 'Shame Nation,' we're giving a voice to the women that have been sexually harassed online," said Scheff, a family Internet safety advocate who was herself the victim of online shaming in 2003. "We're letting you know that these people are just as emotionally ... in pain" as women who are sexually harassed by a boss or colleague.

Twenty-one percent of women ages 18 to 29 said they have been sexually harassed online, more than twice the number of men in the same age group who say they have experienced it, according to a Pew Research Center survey released in July.

The survey found that overall, men are more likely than women to experience any form of online harassment, which includes physical threats and name-calling, but women expressed more concern about it, according to the survey.

Seventy-percent of women -- and 83% of women 18 to 29 -- believe online harassment is a major problem, the survey found, versus 54% of men -- and 55% of young men.

'Who saw me?'

Annmarie Chiarini, a mother of two and a college English professor who was interviewed for "Shame Nation," knows firsthand how painful online sexual harassment can be.

When she was going through the worst of it, she says, she was afraid to leave her house. "I was at my son's soccer practice, and I was looking around at all the fathers there, and I kept thinking, 'Who saw me?' " said Chiarini, whose revealing photos were posted online without her consent, in an interview. "When you are a victim of online harassment, no place is truly safe."

Annmarie Chiarini, a victim of revenge porn, now works to help other victims of online sexual harassment.

Chiarini's experience began with a Facebook request from an old high school boyfriend in 2009, which ultimately led to a romantic relationship. At some point, her boyfriend started begging her for nude photos.

"I was never comfortable with it for a lot of reasons, but ... finally I relented," she said, deciding to share some seminude shots with him.

The relationship started to deteriorate after she says he became extremely possessive and jealous, wanting to know who she was with at all times and accusing her of cheating, so she decided to end it. But her ex wasn't happy and fired off threats: Either she would take him back, or he would put nude photos of her up for auction on eBay. During a call, she says, he told her he would destroy her and then hung up the phone.

The next day, Chiarini said, he followed through on his threat and posted the auction featuring photos of her on eBay. He reposted the photos as quickly as she could request that eBay take them down, she said.

"The first thing I felt really was just, I was embarrassed. I was just embarrassed. I never, just the thought of my sexuality, my body, my privacy being available to others, that was just awful," she said.

She hoped no one would see the pictures, but she would learn that a couple of her students and two of her colleagues saw them.

"I didn't have time to feel angry at him. I didn't have time to feel betrayed. I was panicked. I just wanted it over. I had no one to turn to for help," she said.

She went to the police, who did nothing, she said, telling her that no crime had been committed. At the time, there were no laws in place to protect against this type of online behavior.

She remembers the panic of not knowing where to look to make sure the photos hadn't been shared somewhere else and waking up in the middle of the night on a regular basis to scour the Internet.

"Three a.m. was my witching hour, and for some reason, that's when I would pop awake, and I would have to search Facebook. I would have to search eBay. I would have to google my name. I would have to check all my email accounts," she said.

A year later, she learned that an online profile was created using her seminude images and inviting men to come to her home for sex. She reached out to state police and the FBI for help, and she even contemplated suicide.

"Online abuse is very abstract," she said. "It's the thundering footsteps of an invisible pursuer. You hear it. It's there. It's present. It's 24/7. It's nonstop. It comes at you from all angles, but you don't know, I didn't know who it was."

The site was viewed 3,000 times before a friend figured out how to help her get the photos removed.

"I was so lucky. The average victim who is posted is typically on a minimum of a thousand websites," she said. "There are close to 4,000 websites dedicated to nonconsensual pornography."

After her experiences, she decided to turn her attention to making changes and helped lobby for a new law now in effect in Maryland, making the release of nonconsenual pornographic images a criminal offense.

"I wanted something on the books that would serve as a deterrent with the message that there are consequences for this behavior. This behavior is unacceptable. If you choose to engage in it, there will be consequences," she said.

Many forms of online sexual harassment

Online sexual harassment can take many forms, and Scheff provides numerous examples in "Shame Nation." Those include the case of Jessica Valenti, a columnist with The Guardian who writes about feminism. She announced that she was taking a break from Twitter in 2016 after receiving "a rape and death threat" against her 5-year-old daughter.

At the time, she wrote, "I am sick of this shit. Sick of saying over and over how scary this is, sick of being told to suck it up."

I am sick of this shit. Sick of saying over and over how scary this is, sick of being told to suck it up. — Jessica Valenti (@JessicaValenti) July 27, 2016

Scheff also mentions the experience of actress Ashley Judd. The University of Kentucky basketball fan shared via Twitter in March 2015 how she was called a host of sexual and derogatory names after she accused another team of "playing dirty" during the NCAA Tournament.

She wrote that when she expressed a "stout" opinion during March Madness, she was called "a whore, c---, threatened with sexual violence." She added, "Not okay.' "

When when I express a stout opinion during #MarchMadness I am called a whore, c---, threatened with sexual violence. Not okay. — ashley judd (@AshleyJudd) March 15, 2015

In an op-ed for Mic.com, she wrote that what happened to her is the "devastating social norm experienced by millions of girls and women on the Internet." "Online harassers use the slightest excuse (or no excuse at all) to dismember our personhood. My tweet was simply the convenient delivery system for a rage toward women that lurks perpetually. I know this experience is universal."

Sue Scheff is the author of "Shame Nation."

Scheff was the victim of online shaming in 2003. As an education consultant who worked with families of troubled teens, she was attacked online by what she calls a "disgruntled client" who she says tried to ruin her career and destroyed her emotional well-being.

"When you are being attacked online, you just go into this deep dark place," Scheff said.

The woman started calling her a "crook" and "con artist" and said that she kidnapped kids and exploited families, Scheff said. Trolls started to pile on, and sexual innuendo began, with people posting that they had red panties that belonged to Scheff and asking others to bid on those panties, she said.

"It was so humiliating. It was horrifying," said Scheff, a mother of two. She didn't take any action until she learned from a psychologist who recommended families to her that they weren't going to see Scheff because of what they found when they googled her name.

"What happens is, they always keep coming back, and they keep saying, 'Do you realize who you are referring us to? Do you know what Google is saying about her?' " Scheff recounted the psychologist telling her.

The implications for her were real: a loss of future clients. "If you are being sexually harassed online or if you have any type of shaming online, your employer, your college admissions (officer), anyone, they're not going to take a moment to decide whether it's Internet fact or Internet fiction," she said. "They're moving on to that next applicant."

Scheff ended up suing the person who attacked her online and won a landmark case in 2006 for Internet defamation. She told her story in the book "Google Bomb: The Untold Story of the $11.3M Verdict That Changed the Way We Use the Internet."

She was motivated to write "Shame Nation" after hearing about the tragedies connected to online bullying and harassment, such as the case of Tyler Clementi , a college student who committed suicide after a sexual encounter with a man was streamed online.

"I remembered that dark place that I felt, that place of hopelessness, that place of 'should I end my life?' which I never would," she said. "Being 40-something years old, I had the maturity to know that, you know what, it's going to get better, so this is the importance of a book like 'Shame Nation' to let people know that you can survive it, there are ways to prevent it, and the best part about it is you can overcome it. You redefine your life after you've been shamed."

Advice if you've been harassed online

Her advice to anyone who has faced online sexual harassment or any other online shaming is to report the harasser to the platform and flag it as abusive. Many women are afraid to report it because they may feel embarrassed or humiliated, or wonder if they brought it on themselves.

"I mean, I know initially ... I was like, 'Oh, my God. Did I do something wrong? What did I do?' ... You're thinking, 'Oh, my God, will the authorities think that this was my fault?' And that is sometimes enough to prevent you from wanting to report it, and that's how this escalates, and this is how men or a perpetrator can get away with it," Scheff said.

Samantha Silverberg is a licensed professional counselor who works with Online SOS, a nonprofit that provides confidential and professional support to people experiencing online harassment. In "Shame Nation," she tells Scheff that the most important thing she can do to help victims is make sure that they realize they didn't do anything to deserve it.

"There's a lot of negative self-talk that comes up with you experiencing something like this. I challenge them with evidence. ... People think, 'This only happens to me, and it's something about me,' " Silverberg said.

Chiarini, the victim of revenge porn, also encourages people to collect evidence, which includes taking screen shots and printing out everything related to the abuse. She also says they should research the laws in the state where they live and where their perpetrator resides.

There are also online resources such as the Cyber Civil Rights Initiative , which has a guide on how to remove photos that were posted against a person's will, and groups like Online SOS, which provides counseling support.

Scheff says victims should tell a friend, because they won't be able to tackle this on their own. "A lot of people try to go at this alone and I did it. For months, I didn't tell anybody. I felt embarrassed. You feel humiliated but tell a friend."

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"Definitely, definitely, definitely talk to someone," Chiarini agreed. She said that her therapist was her lifeline and that as she talked to more people about it, she realized she was not alone.

"Reach out to people. Anybody who's been through this, anybody who works for these nonprofits ... we will stop what we are doing and help you because we know what it's like," she said. "People are so afraid to reach out and to share their story."