“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.”

The captains are ALL WOMEN, and Airbnb really helps endeavors like this:

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.

It will be interesting if this and Airbnb are a true culture shift.

Will they be around in five years? I'm not sure. But it's an interesting experiment to watch play out.