Home Base: New York City
Year Founded: 2011
Power stat: Nestio has partnerships with eBay Classifieds, Citi Habitats, Curbed, Naked Apartments, and a half dozen other listings sites.

"August will be my 10-year anniversary in New York," Caren Maio explains. "I have moved a lot in these 10 years, and I have seen a lot of inefficiencies in the [real-estate] market." From those nail-biting, teeth-gritting frustrations, she built Nestio, a one-stop real-estate-rental hub where users can catalog listings and add their own photos and notes for others to see. The real added value: Users can choose collaborators (like a significant other or roommate) and share listings across social media, seeking feedback from friends who'd notice if there wasn't a sink in the bathroom if you did not. After gaining their footing in NYC, Maio and her cofounders took their baby nationwide in October. "New York moves so fast. It's crazy," she says. "It's nice to be in other markets where it's not as competitive and people take their time."

What it's like to develop a company culture from nothing: "It's funny for me because I have only known big companies and politics. You know, you work nine to five. You have an hour lunch. And I knew that I didn't want to create a culture like that. The guys [her cofounders] came from a start-up where you work hard, but you play hard—and you treat your employees right. For us, hiring our first employee, we were growing the company by 25 percent—it was really important that the new person felt like he had a say. At the end of the day, when you are competing with huge organizations in New York, you can't compete on a salary scale. What we can compete on is a sense of ownership over product."

Her single worst apartment hunt: "It was my first apartment. I went to NYU, and I decided, 'Okay, I'm done with the dorms. I'm going to be a real New York girl and rent an apartment.' But I didn't know the ins and outs of co-ops—it wasn't explained to me that you needed approval. I moved in; they didn't like that an NYU student was living in their building, so 30 days later I had to leave and look for a new apartment. That was pretty crappy."

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