In a quiet cafe outside San Francisco, "Josephine" -- a local prostitute -- arranges a collection of t-shirts across the table. They're emblazoned with phrases like "Winter is Coming" and "Geeks Make Better Lovers." She wears them in her online ads to catch the eye of the area's well-off engineers and programmers.

"I'm trying to communicate to them that I understand a little bit what it's like to be techy, nerdy, geeky," she says. There's another thing Josephine and her clients have in common: Like many of the techies she caters to, Josephine views herself as an entrepreneur.

"I consider myself to be a small business owner," she says.

The Bay Area's high wages and concentration of young guys with disposable income have made it a magnet for sex workers -- a broad term that can refer to a number of services, including sexual massage, prostitution, and escort and dominatrix work. "It seems like a lot of out-of-town providers come into town to work in the Valley," says "Karen," who charges $500 an hour and caters to the area's tech executives. (To protect their privacy, CNNMoney agreed to use pseudonyms or the professional names of those we spoke with for this story.)

It's no surprise that a region where a sizable population is flush with cash has a thriving adult services industry. What's more intriguing is how those in the industry are using both the tools and the language of the area's tech startups to build their businesses -- and to try to change the public perception of their work.

Kitty Stryker, a self-described "steampunk courtesan" who rents her time for $350 an hour on up, has a day job as a social media marketer for a local startup. She uses the same apps to grow her evening business.

"Everything I know about social media marketing I learned doing sex work," she says. "Currently I'm using Hootsuite a lot; I'm using Klout a little bit. I also use Twitter calendar, which is just this simple free thing, but it's got very interesting analytics data."

Stryker is a vocal advocate for the right of women to choose sex work and pursue it safely. She's proud of her job and spoke about it recently on "The Whorecast," a podcast created by Siouxsie Q, a stripper, sex worker and activist. (The show was originally called "This American Whore," until a dispute with NPR, which airs "This American Life," prompted a recent name change.)

"I consider the sex work that I do my career," Siouxsie says. "I would like the podcast to be a vehicle to really humanize sex work and have people see that I am just a girl trying to make a living and pursue the American dream."

Siouxsie goes about building her client base in ways that will sound familiar to many small business operators.

"I have a Tumblr, Instagram, Facebook, Twitter, I have two websites, and I have Google Voice," she says.

Twitter is an especially good marketing tool for her for video business, which includes live shows where viewers can pay to interact with her. "When I'm doing a shoot or I'm doing a cam show, I will absolutely take pictures and put them out there and say, 'Hey, this is what you're missing out on.' The more I tweet, the more folks end up in the chat room."

Like the startup founders who flock to the Bay Area, sex workers see their own potential for striking gold.

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"There's a lot of competition to get the big-name clients," says Karen, who estimates that she's made close to $1 million over the decade she's been working in the area. "When you do land them, I've heard of women getting condos, whatever they need."

Unless minors are involved, prostitution is typically a lower-priority crime for law enforcement agencies. In San Jose -- the sprawling city that calls itself the capital of Silicon Valley -- the vice unit was disbanded in 2011 because of budget constraints. Still, prostitution arrests rose 35% last year.

"Business is good out here," says Sgt. Kyle Oki of the San Jose Police Department. "The girls say they can make more money here than in other cities."

Sgt. Oki works on San Jose's Human Trafficking Task Force, which focuses on stopping coerced prostitution. He sees technology as one of the sex trade's biggest growth drivers. With websites and smartphones, buyers and sellers who would never be comfortable trolling out on the street in public can arrange for discreet transactions, he says.

Those same tools are helping sex workers set the terms of their employment.

"When I first started, the online presence was really limited to the gentlemen, who were looking for women to hire," says Josephine. Those "hobbyists," as regular clients call themselves, have dozens of review sites where they can offer appraisals of the providers they frequent.

Now the women are turning the tables. "I'm beta-testing a program right now, a national registry for sex workers," Josephine says. "I go in and put in information about my clients in a very discreet and very secure way."

Siouxsie Q says she finds sex work "very feminist and very empowering." The paychecks are a big lure, she admits --"I live a fairly extravagant lifestyle for a 27-year-old living in San Francisco. I go out to eat, I buy nice clothes, I go on trips." -- but she also likes performing and interacting physically with her clients.

Any paying job involves work, she points out.

"I'm quoting Belle de Jour, who did Secret Diary of a Call Girl, but you know, you sell the strength of your arms when you dig a hole. Selling our bodies -- which everyone thinks of as this big scary thing -- anyone who has a job that requires labor does that."

Josephine says her tech-themed online ads are both a marketing ploy and a savvy business move: They help bring in a clientele she says she genuinely enjoys spending time with. In her off hours, she goes to cons, dabbles in programming, and watches Game of Thrones.

"I like to bring in the kinds of people who I like being around," she says.

Karen's clients -- almost all of them from the tech industry -- are "young guys who have the money to spend on what they need," she says. "When they're working long days, this is something they simply see as what they need."

Stryker has a similar outlook. She's a comics fan with tattoos of molecules on her neck who considers herself a natural-born nerd, and is happy to "train" geeky clients on how to interact with those they're smitten with.

"You explain it to them in a way that's like a formula," she says. "Then they say 'ohhhh, math. It's math. Eventually if I plug these things into the formula, it will work.' I speak geek. It's a way we can communicate that they understand."

Stryker's business tends to rise and fall with the tech industry tides, she says, and right now, it's booming. "People are starting to feel like they can treat themselves a little bit more."

Josephine also says her clients are feeling more secure and spending freely again, after a big drop-off during the recession.

"It's interesting to hear on the news about the economy and how it's recovering," she says. "If you were to gauge by my business, it's recovering a lot faster."