One night a young Palestinian man living abroad fell victim to an online scam, involving a web camera and a beautiful woman. Here Samir (not his real name) tells the story of how he was trapped - and below the BBC's Reda el Mawy visits the Moroccan boomtown where many of the scammers are based.
WARNING: this story contains descriptions of sexual acts
It happened when I was home alone. This girl added me on Facebook. I didn't think it was anything strange - I often get friend requests from old school friends who I don't know well.
The next day she sends me a message: "Hi, how are you? I saw your profile and I liked you." So I looked at her profile and, I mean, she was really hot.
That night she starts messaging me via Skype. She says she's 23, her parents are dead, and she lives with her older sister in Sidon, Lebanon. She says she's bored because she doesn't study or work and that her sister is very strict. I ask her about her hobbies and she says she likes sex. She loves it, she says.
"Hmm," I thought, "this is interesting." At this point I am curious but unsure, because it's strange how easily she's talking about sex with a stranger. But I was bored, my girlfriend was out of town, and didn't have anything to do. So I figured, "What the hell, I'll chat with this girl and see where it goes."
Eventually she asks if I have a webcam. So I turn on my video and say, "Can I see you too?" She turns on her video and when I see her, you know, she is a really beautiful girl. With a girl like this, you lose your head.
We continue chatting, but only in messages, not actually speaking. She says she's afraid her sister will hear her. As we're chatting she tells me that talking with me is turning her on. I'm thinking because she lives with her strict sister, in the south of Lebanon rather than in a more open place like Beirut, maybe she's frustrated and looks for sexual encounters online.
Then she asks me to show her my penis. So I show her my penis. Then I say, "OK, your turn." She lies on the bed, undresses, and starts masturbating. I'd never seen anything like it. It was so easy. Too good to be true.
So I start masturbating too. She tells me to put the camera on my face because it excites her, so I move the camera back and forth between my face and my penis. After a few minutes she pretends to have an orgasm. Still naked, she comes back to the keyboard to chat with me. She asks me what I do, and I tell her I work in marketing in Milan.
"Oh, so you must be rich!" she says.
"Well, I get by," I say.
Then she says she hears her sister coming, so she gets dressed and signs off.
A half hour later I get a message on Facebook. "Listen," it says, "I'm a man, and I recorded a video of you masturbating. Do you want to see it?" He sends me the video. It's about five minutes of me masturbating.
"I have a list of your friends and family from Facebook - your mum, your sister, your cousins," he says. "You have one week to send me to send me 5,000 euros (£4,450), or I'll send them the video."
I was in shock. My first thought was to send him the money immediately. But I cancel her, or him, as a Skype contact and right away I get a message on WhatsApp.
"I'm here," it says.
This is one of a series of stories looking at a new and disturbing phenomenon - the use of private or sexually explicit images to threaten, blackmail and shame young people, mainly girls and women, in some of the world's most conservative societies. Explore all the stories and join the conversation here.
So I plead with him. I tell him I don't have 5,000 euros. He says, "Of course you do, you have a good job in Europe." "No," I tell him, "that was a lie, just to impress the girl, I'm just a pizza delivery guy."
Then I remember a photo I had sent her of me tiling my bathroom and I say, "Look, do you think if I were some rich guy I'd tile my own bathroom?"
He's sort of convinced by this and says, "That may be true, but I don't care. You have one week to send me 2,000 euros. Otherwise, I'm sending the video to your family."
I try to calm down and think rationally. If I send him money, what is to stop him from coming back and demanding more?
Then it occurs to me that if he sends the video to my contacts - people he isn't friends with - it will go to a junk inbox that no-one checks. And even if they check it, I figure, who is going to open a video file from an unknown person? It could be a virus. So I have two choices: I send him the money and I have no guarantee he doesn't ask for more, or I refuse and hope no-one looks at the video.
The day comes, though, when he messages me and says, "OK, I'm about to upload the video to YouTube."
"Upload it," I tell him. "I don't care any more."
Then I change my privacy settings so no-one can post to my wall or tag me without my consent.
Then he sends me the link to the video on WhatsApp. I watch it again. It's me masturbating, on YouTube. I feel sick to my stomach.
Immediately I start reporting the video to YouTube for sexual content. I report it, close the page, reload the link, and report it again. Over and over.
He sends me a message saying he's about to send the link to my relatives on Facebook if I don't pay.
"Go ahead," I tell him, "send it."
I couldn't pay him. First 2,000 euros, then perhaps 5,000. Where would it end? He was so upset. He starts sending me insults, telling me he'll send the video to my mother, to everyone I know.
I keep reporting the video. Each time I'm watching the number of views to see if anyone else has viewed it. After about an hour YouTube takes the video down.
From what I can tell, all the views were mine, except for one. That could have been him viewing it after he uploaded it, or one of my relatives. I'll never know for sure, but I've never heard from anyone. Maybe a male relative saw it and never told anyone.
Can you imagine, though, if an aunt had seen it? She would have told another aunt, her husband, her kids, soon my whole family would have known. I have family all over the world, the US, Canada, Australia, Saudi Arabia, the Gulf states, Europe.
And what if my mum sees this? A video of me masturbating. I would have thrown myself out the window from the shame.
After the video was taken down I didn't hear from the guy again. I imagine he moved on to bigger fish. I remember when I asked why he was picking on a poor young guy like me he had said, "You think I don't target rich guys in the Gulf states? Of course I do. You're lucky I can see from your Facebook page you're not married, or I would be asking for a lot more money."
I think it's over, but every now and then I check YouTube to see if he's re-uploaded it.
Reda el Mawy writes: The "23-year-old Lebanese girl" who seduced Samir on Skype was almost certainly a young man from Oued Zem - a small town in central Morocco that has become known as the capital of the "sextortion" industry.
The Oued Zem scammers trawl Facebook for victims, and as soon as a man answers a video call - either on Skype or, increasingly, within Facebook itself - they activate software that shows the victim a pre-recorded video of a girl downloaded from a porn webcam site.
They are so familiar with this video that they are able to chat-message their victims at exactly the points where the girl appears to be typing on the keyboard.
"We ask him to take off his clothes and to do obscene gestures," says one young scammer I will call Omar.
"It's crucial that his genitals are visible while he's doing these gestures. This is filmed with his face on screen so the video looks credible. When we've got the recording we upload it to YouTube and send it to him in a private message. That's when the threatening starts. We spend 20 minutes chatting, 20 minutes for the video, and 20 minutes threatening - threatening and negotiating. They all pay."
He adds: "The weak point of Arabs is sex. So you look for their weaknesses, and you exploit them. The other weakness is when they are married, for example. You can exploit that. Then there are the really religious guys. You see someone who looks like a sheikh, carrying the Koran, and you think, 'There's no way he'll fall for this - but let's try him anyway.' And when you try, he falls for it."
Omar says he earns about $500 (£400) every day from the scam, and that hundreds of other young men in Oued Zem are doing the same.
I counted at least 50 international money transfer offices in the town. The manager of one of these offices told me that he took in about $8,500 (£7,000) every day, and that the vast majority of that was blackmail money. There are German cars and Japanese motorbikes in the streets, and fancy café-restaurants that provide a front for families that need an explanation for their new-found wealth.
In the UK, Wayne May runs an online community, Scam Survivors, that offers advice and support to victims of the webcam masturbation racket. Since 2012 he has received more than 14,000 requests for help from victims all over the world, including the UK and the US. Many are young Arab men, he says, and about a third of all the scams originate in Morocco.
Before the advent of social media, Oued Zem was largely reliant on remittances from people working in Europe. But with the economic crash of 2008, remittances dropped - and this was exactly the moment that Facebook and webcams were becoming everyday tools of communication.
Salaheddin El-Kennan, a labour activist, does not blame the town's young men for making money from extortion. He points the finger at the state-owned company that mines phosphate in the surrounding countryside but employs very few local people.
"I chose not to go down the route of scamming because I consider it incompatible with our Moroccan and Islamic values," he says.
"But unemployment rates in our town are higher than in the rest of Morocco. Nationally, unemployment is at 8.7%, while in our town we estimate that it's as high as 60%. With the lack of employment, and no apprenticeship schemes in the city, many people look for other ways to make money."
Omar said he was not proud of what he does, and that he wanted to stop scamming.
Intelligent, articulate, and technologically adept, it is hard to avoid the conclusion that in a place with more opportunities a young man of Omar's talents could find a legitimate way to earn his $500 a day.
Reporting by Sean O'Neill, Reda el Mawy, and Daniel Silas Adamson