It all started with a “cryptic” Craigslist ad and a 400-square-foot beach hideaway. But no, it’s not that kind of story.

Cliff Johnson was a Bay Area tax attorney seeking a new direction in life. And so—obeying the homing signal that sends such folk north—he hoped to start a business in Portland. A vaguely worded online posting landed him in the Forest Park home of Eric Breon, a financial analyst with a simpatico entrepreneurial bent.

“We were both interested in doing something that had a greater purpose,” Johnson, now 34, recalls. “In San Francisco, people want to start a tech company and spin it off. Eric and I were both interested in something built to last a little longer. That’s just an easier conversation to have in Portland.”

Just months after this meeting, in March 2010 the pair launched Vacasa, an online service to manage vacation rental properties. They started with a single place, a Breon family beach shack on the Washington coast. Today, Vacasa runs 2,600 properties. Double-take expansion—from $230,000 in revenue its first year to nearly $100 million annually; from Eric and Cliff to more than 150 Portland employees and hundreds more in the field—has earned Vacasa headlines as one of the city’s fastest-growing companies. (Ironically, it currently manages no homes in Portland, due to city regulations.) For Johnson, now Vacasa’s chief development officer, the company is just getting started transforming its field.

“It was stunning how far behind the industry was technologically,” he says. Vacasa’s proprietary algorithm adjusts each property’s nightly price in real time, based on demand—if it’s dead in Galveston one weekend, the algorithm knows. The company as a whole quickly evolved from a booking agency to a full-service property manager: hand Vacasa the keys to the vacation rental you own, and it handles all marketing, booking, and maintenance, mostly through local managers. (“Property owners either want to hand over everything, or nothing,” Johnson says.) Besides booking properties through its own site, Vacasa lists properties via services like Airbnb and FlipKey, making those titans less competitors than marketing vehicles.

Johnson is responsible for expanding the company’s reach into new markets, and he nurtures a vision that goes beyond cleaning and stocking bathrooms. Vacasa has, for example, begun awarding small seed grants to start-up businesses in towns where it runs properties. “We want to be the antithesis of Walmart,” he says. “We’re not looking to own the coffeeshop. We want the places we operate to become better places to visit.”

So the lesson: vague business schemes on Craigslist can lead to good things. (Results may vary.)