Online payback is promting calls for new protective laws, writes Cosima Marriner.
One in 10 Australian adults has had a sexually explicit image of them sent to others without their permission, prompting fresh calls for the federal government to outlaw revenge porn.
The first national survey of digital harassment and abuse has also highlighted how perpetrators of domestic violence are increasingly using technology to harass, stalk and threaten their victims, heightening the effect of the abuse. 
Researchers from RMIT and La Trobe University surveyed 3000 adults aged 18 to 54 to gauge the prevalence of digital harassment and abuse in Australia. They also interviewed police officers, lawyers and sexual and domestic violence support workers.
Sixty per cent of adults have been harassed or abused online, with young adults aged 18 to 24 the most likely to be victims. Although men and women have experienced harassment in equal numbers, perpetrators are twice as likely to be men as women.
The most common form of abuse is offensive language, followed by malicious lies being spread online, being sent unwanted sexual content, and having embarrassing photos posted without the subject's permission. Perpetrators are most likely to be strangers.
RMIT's Anastasia Powell said her study had uncovered significant levels of image-based sexual abuse. One in 10 adults has had a nude or semi-nude picture of them taken without their permission. The same proportion has had a sexually explicit image of them sent to others without their permission, or had someone threaten to share such an image publicly.
"It's the first Australian study to show the prevalence of this kind of image-based abuse," Dr Powell said. "Interestingly, both men and women report this is happening to them in the same numbers."
La Trobe's Nicola Henry said the harm was magnified by the massive potential audience for revenge porn. There are now underground revenge porn websites where people trade non-consensual images for bitcoins.
"A lot of women have no idea that it is going on," Dr Henry said.
The researchers said there needed to be better legal protection for victims of digital abuse and harassment. Police are particularly keen for a specific revenge porn offence, as existing laws are too broad for them to be confident of a conviction.
"Technology and its uses are advancing quicker than the law can keep up," Dr Powell said. "We need a revenge porn law, reflecting that this is happening to one in 10 Australians. It's a really important gap."
She also called for consistency in state and federal laws so victims don't fall through gaps.
Prime Minister Malcolm Turnbull has said he is "certainly open" to making a specific legal provision for revenge porn.
"To threaten a woman ... with publication of intimate photographs is thoroughly unacceptable conduct," he said when announcing $100 million in funding to fight domestic violence.
The COAG advisory panel on reducing violence against women is considering whether current laws are adequate to guard against technology-facilitated abuse. The federal government is waiting for the panel to report back by the end of the year before it acts on revenge porn.
Minister for Women Michaelia Cash said there had been a "worrying rise" in such incidents.
Police and sexual assault services have identified three "highly concerning" trends in relation to image-based sexual abuse. Aside from revenge porn, sextortion is also occurring, whereby a perpetrator uses sexual images to coerce a victim into unwanted sexual conduct. In addition, police warned that sexual assaults are being photographed or filmed, and then used to intimidate or silence the victim.
Domestic violence support services said technology was enabling perpetrators to harass their victims 24/7. This includes persistent unwanted contact via texts, emails and social media, bombarding victims with threats, and installing stalker apps on the victims' devices without their knowledge to monitor their communications and location.
Women are much more vulnerable to sexual harassment online than men. They are also more likely than men to act to stop the harassment, by telling the perpetrator to stop, changing their profile settings, leaving the site or turning off their devices.
"Given the extent that technology is embedded in our everyday lives, the idea that women might be withdrawing from online participation because of harassment is very concerning," Dr Powell said.
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Under attack
Examples of abuse provided to the study
6 in 10 adults have experienced digital harassment and abuse
10% of adults have suffered image-based sexual abuse
"A man was drugging his wife so when she was asleep she would basically be comatose. He was sexually off ending against her, and taking videos and photos, and uploading them and sharing them with like-minded individuals."
"She's met a male and she's given him her phone number, they're started communicating and she said she's not interested. [But] he keeps stalking her via the mobile phone and sending her pictures of himself naked and then quite rude pornographic text messages to her and . . . he wouldn't take no for an answer"
"He advertised on Gumtree for English exchange or English friendship and conversation and our client took him up on that off er and started a sexual relationship. He took photos of her naked and then blackmailed her that he would then send it to her family . . . and he did, he sent it to everyone in her inbox."
Top 5 forms of abuse
1. Offensive language (44% of adults experience this)
2. Malicious rumours or lies spread online (37%)
3. Unwanted sexually explicit images, emails, texts (29%)
4. Embarrassing photos posted online without permission (29%)
5. Physical violence threats (26%)
SOURCE: DIGITAL HARASSMENT AND ABUSE OF ADULT AUSTRALIANS, RMIT, LA TROBE UNIVERSITY