At least 3,000 porn websites around the world feature the revenge genre, and the number is rising, says John Di Giacomo of Revision Legal, a Michigan-based law firm. Women’s charities in Britain and America say more victims are contacting them for help all the time. (Men are occasionally targeted, too.) In Japan the number of cases reported to police more than tripled, to 27,334, between 2008 and 2012.

The consequences for the unwitting subjects can be severe, including damage to their future relationships and careers. Ms Chiarini was harassed online. Others have had abusive strangers turn up at their doors. In the past couple of years several are known to have killed themselves.

Yet victims often find themselves without legal recourse. Many countries have laws against harassment or “malicious communication”, but these generally target repeated actions, direct contacts and verbal or physical threats. Copyright law cannot help if the person who publishes an image also took it. Even if it was snapped by the subject (one survey suggests that such “selfies” make up a large share of all revenge porn), getting it taken down is slow and costly. And during the delay it may be republished elsewhere.

If images were stolen or obtained by subterfuge, a victim may have some redress. In February a jury in Texas awarded $500,000 to a woman whose ex-boyfriend posted a pornographic video he recorded during a Skype call. But few victims bring such cases. Costs can reach $100,000 and legal proceedings will draw unwanted attention to the images. And most countries absolve websites that host user-generated material of legal responsibility for it. (Child pornography is usually an exception.) After “basically begging” a site to remove images of herself, Bekah Wells, a Florida student, found her written appeal and photos featured on its home-page.

Laws against child pornography and hacking can sometimes be pressed into service. In March a court in Ohio awarded a client of Marc Randazza, a lawyer in Las Vegas, damages of $385,000 against Kevin Bollaert, a Californian, since the client was under 18 in photos featured on his site, UGotPosted. Also facing prosecution and possible jail time is Hunter Moore, who the FBI claims paid a hacker to source images for his now-defunct site, IsAnyoneUp.

Mr Bollaert also faces prosecution for extortion, which could lead to years in jail. He is charged with having made tens of thousands of dollars from another site, ChangeMyReputation, which would contact UGotPosted’s victims to alert them to the publication of their images—and offer to get them removed for $300 or more. Klein Investigations and Consulting, a Texan firm, says that since the beginning of last year it has found seven American sites that offer to remove content if the subject pays. All have since closed in the face of litigation or prosecution. It has also sent evidence to Interpol relating to eight similar operations based elsewhere.

But site owners can still make money, if they are careful, by running paid ads for “arbitration” or “reputation management” firms that negotiate with sites on behalf of victims. According to Mr Randazza, if customers can choose between several firms that are independent of the site publishing the images and do not guarantee results, extortion charges are unlikely to stick.

Ex-deletion

As lawmakers and politicians around the world wake up to the spread of revenge porn, more are trying to craft laws against it. Israel has gone furthest: in January the Knesset voted unanimously to make posting intimate images without the subject’s agreement count as sexual harassment, punishable by up to five years in jail. Previously such actions were regarded as mere violations of privacy. Police rarely investigated, let alone sought to prosecute.

The new law has changed attitudes, says Yifat Kariv, who sponsored it in the Knesset. But establishing beyond doubt who first disseminated an image is hard. An ex-boyfriend may claim, for example, that the images were stolen when his computer was hacked. In the past four months Israeli police have opened files on 55 cases, 37 of which are still being investigated. So far just one has led to an indictment.

Britain is also planning revenge-porn laws. Chris Grayling, the justice secretary, told parliament on July 1st that the government may include them in a criminal-justice bill planned for the autumn. Julian Huppert, a Liberal Democrat MP who campaigns on the issue, thinks that even if prosecution is rare, the mere possibility will act as a deterrent. Many of those who post revenge porn are quite open about it, he points out. “They think it’s funny.”

New law is being shaped in Germany, too. In May a court in Koblenz ordered a man who possessed erotic photos and videos of his ex-girlfriend to delete the most explicit ones on her request—though they had been shot with her permission and he had neither shared them nor threatened to do so. The potential for harm to her outweighed his rights as the images’ owner and copyright holder, the judge said. Both are likely to appeal: she wants them all deleted, even the tamer ones, and he is unwilling to give up any of them.

American politicians and lawmakers are just as keen as those elsewhere to tackle a new menace that has captured broad public attention. Several states, including California and New Jersey, have passed laws targeting revenge porn, and more are planning them. Jackie Speier, a Californian congresswoman, is pushing for a bill that would make online dissemination of the material a federal crime.

But these efforts, Mr Randazza says, may end up producing nothing more than “chicken-soup laws—they make everyone feel a little bit better but they don’t really do anything.” The difficulty is crafting laws that manage to criminalise at least the most egregious cases without falling foul of the protections for free speech guaranteed by the constitution. Those that are drafted too broadly may eventually be overturned by the Supreme Court, says Viktor Mayer-Schönberger, a specialist in global internet law at Oxford University, just like an overly sweeping federal law passed in 1996 after a panic about online child pornography.

Free-speech campaigners also fret about cases such as that of Anthony Weiner, a former American congressman with an apparent penchant for sending women photographs of his penis. A loosely drafted law could have made it impossible for his targets to publish the evidence without committing a crime. When novel harms arise, says Mr Mayer-Schönberger, “legislators feel they need to act. And typically, they overreact.”