SAN FRANCISCO -- From the outside it's just a beige three-story building in a quiet residential neighborhood. But inside, in a third-floor apartment, there are enough Ikea bunk beds to sleep 10 people, crammed into two bedrooms. The living room is bare except for a futon, a tiny desk and laptop power cables strewed across the hardwood floor like a nest of snakes.
The tenants, mostly men in their 20s, sleep next to heaps of dirty laundry. There is no television set; the men watch online video, on laptops with headphones. On a recent afternoon, 23-year-old Steve El-Hage, who came here from Toronto in May, ate slices of ham straight out of the package: "As you can see, I was going to make a sandwich, but I didn't get there."
This is not some kind of dorm, but a "hacker hostel." It's one of several in the Bay Area that offer short- or long-term stays for aspiring tech entrepreneurs on the bottom rung of the Silicon Valley ladder, those who haven't yet achieved Facebook-level riches. These establishments put a twist on the long tradition of communal housing for tech types by turning it into a commercial enterprise.
The San Francisco hostel is part of a minichain of three bunk-bed-stuffed residences under the same management, all places where young programmers, designers and scientists can work, eat and sleep.
These are not so different from crowded apartments that cater to immigrants. But many tenants are here not so much for the cheap rent -- $40 a night -- as for the camaraderie and idea-swapping. And potential tenants are screened to make sure they will contribute to the mix. Justin Carden, a 29-year-old software engineer who is staying in another hostel, in Menlo Park, while working on a biotech start-up, talks about the place as if it were Stanford.
"The intellectual stimulation you get from being here is unparalleled," Mr. Carden said. "If you're wanting to do something to change the world and make it a fundamentally better place, you need to be around the right people."
Hackers -- the Mark Zuckerberg variety, not the identity thieves -- have long crammed into odd or tiny spaces and worked together to solve problems. In the 1960s, researchers at the Stanford Artificial Intelligence Laboratory slept in the attic and, while waiting for their turn on the shared mainframe computer, sweated in the basement sauna.
When told about the hacker hostels, Ethan Mollick, an assistant professor at the Wharton School of the University of Pennsylvania who studies entrepreneurship, said they reminded him of his days in the last decade studying at M.I.T., where graduate students would have bunk beds inside their small offices.
"We work so hard and we don't care about where we're staying," he said. "That's how you learn. People always complain that academic study of computer science doesn't do a lot for you as a programmer. What does are these sorts of environments."
Airbnb, a popular Web rental service for apartments or single rooms, has helped commercialize this idea. A quick search for "hacker" on the site turns up dozens of listings in the Bay Area. Not all the operations are above board. Katy Levinson, who runs another hacker house, declined to give its exact location because she had heard about several houses being shut down after running into trouble with landlords.
The other houses run by the operators of the San Francisco apartment, who call themselves Chez JJ, are in Mountain View and Menlo Park. Each one has a host, or "captain," who sifts through the requests pouring in on Airbnb from would-be guests.
The captains, all women, screen for personalities and occupations, rejecting applicants who are not techies or simply have a poor attitude. Sasha Willins, a 26-year-old graphic designer who is captain of the San Francisco apartment, has a gentle way of saying no. "It's not so much rejecting as it is asking so many questions until they withdraw their application," she said.
New guests get a pillow, comforter, sheets and a towel. The captains occasionally cook meals for everyone, like a pancake brunch with mimosas. As payment, the captains get free rent and a private room.
The idea for the minichain came from Jade Wang, a 28-year-old neuroscientist who has worked at NASA and started Chez JJ with her friend Jocelyn Berl. She said she once rented out a spare bedroom through Airbnb and realized that "nerds" like herself want to be around their own kind.
"It's not that nerds are necessarily socially awkward among normal people," Dr. Wang said. "If you have a large room of 99 percent nerds and you have that one normal person, they'd be the ones who are socially awkward."
Each Chez JJ house has a different vibe. The Mountain View house tends to be oriented toward start-ups, with many of the residents working on new apps or Web sites. They try out their sales talks on one another before pitching investors.
The house in Menlo Park, which is moving to Palo Alto this summer, is more science-oriented. The captain, Casey Greene, is a 26-year-old molecular biologist, and some of her guests are science students in summer programs at Stanford. They run a journal club, where guests huddle together to discuss scientific papers.
The San Francisco apartment is considerably smaller than the others. On a recent stay there, it felt dormlike, with occasional grime in the bathrooms and piles of dishes in the sink. Some tenants stay a few days; others settle in for months while they search for more permanent housing.
Mr. El-Hage and his business partner Nelson Wu, a 27-year-old electrical and computer engineer, lived there for two months, using it as the headquarters of their start-up, MassDrop, which helps people buy items as a group to get a better price. Mr. Wu spent most of his days sitting on the living room futon and pounding away on his MacBook Air, often until 3 or 4 a.m.
When the site started in May, $12,000 in orders for a car diagnostics device poured in right away. PayPal, which the founders used to process payments, decided their account was "high risk" and suspended it, freezing their money for six months, Mr. Wu said.
Mr. Wu and Mr. El-Hage maxed out their credit cards to fulfill the orders. Without investors backing them, they nearly went broke. MassDrop has recovered to "above-ramen status, but not that much higher," Mr. El-Hage said.
But the two men have since moved out of the apartment. They recently hired their first employee, an 18-year-old student they had met there.
This article originally appeared in The New York Times.