Kari Lerum, a sociologist at the University of Washington, Bothell, where she studies the sex industries, said camming could provide more comfort and autonomy than other sex work. “The women work out of their homes, it’s safe, they have more control over working conditions,” she said.

Lawrence Walters, a Florida lawyer who is an expert in obscenity law, said that there was nothing inherently illegal about cam shows, as long as the models were over 18.

There is another risk. “There’s a perception that you can be a stealth webcam model,” he says. “That’s not always the case.”

Serena Blair, the stage name of another cam model, studied biology at a major university, but came to camming in 2011, frustrated that she couldn’t find a research position that paid more than minimum wage. Now, in a good month, she said, she makes $8,000 in tips. But the choice to become a cam model carries a burden: she fears her parents would shun her if they discovered how she earns money. She can’t put camming on her legitimate résumé, and not long ago she worked a night at a strip club, something she thought she would never do (and vows she won’t do again).

Lacey has faced more immediate problems. Two years ago, a particularly heavy tipper started making demands about what outfits she should wear. He became threatening. Afraid of losing his tips, she initially acceded to his demands, but then stopped. Soon after, her real identity started showing up around the Internet, tied to her cam name and her real address.

She went to the police, but was told there was nothing that could be done; putting real information on the Internet is not illegal. (She did get the sites where her information appeared to take it down.) Then, she found out that the same man had outed several other models, or threatened to. “My big fear is he would call my parents and tell them. If that happens, I will deal with it, but it won’t be pretty if it does,” Lacey said, adding: “Camming is like doing small-scale porn. Your image is out there forever. You have to be O.K. with that before you get into it.”

Some cam models said they weren’t prepared. “Camming is an incredibly isolating job,” wrote one woman, echoing the sentiments of others reached on an Internet forum for cam models, noting she was confident and happy on camera and increasingly withdrawn in the real world. “I spent so many hours a day” being the person she was on the webcam, she wrote, “that I have days where I no longer feel like my real self.”