Airbnb: No place like someone else's home

— -- It's billed as a "cozy and exceptional pool cabana" with a queen bed, "amazing 5-headed shower" and a "genuinely special location where connections deepen, hearts open and peace is found."

I've booked this yoga center retreat via Airbnb.com, a 4-year-old, rapidly expanding vacation-rental service that lets socially minded travelers stay in strangers' beds — or entire homes.

The professionally staged photos? Gorgeous. The four (first-name only) reviews? Glowing. And the rate of $150 per night, not much more than what we would have paid for a room at the Motel 6 in this tony resort town? A certifiable bargain — at least until I factor in the additional $75 cleaning charge, strict cancellation policy and 12% booking fee to Airbnb.

Within minutes of our arrival at the one-acre, Spanish-style compound in a residential neighborhod about a 15-minute drive from downtown Santa Barbara, my husband and I are quaffing complimentary poolside gin and tonics with owners Jenn Houser, 42, an international business consultant, and Martin Clarke, 50, a veteran commercial airline pilot.

Granted, our cabana bed lacks a box spring, the lightbulb on a bedside table has burned out, and there's no closet or hooks for our clothes. And yes, it gives me pause when Clarke confides that the absent Airbnb host with whom I'd exchanged e-mails is actually their long-term renter — and that he, Houser and their disarmingly energetic Tibetan terrier, Tenzing, had flown in from Montana to make sure we were on the up-and-up.

The couple's tenants started listing on Airbnb this spring, and the arrangement is "still a work in progress," says Houser, who adds that she wouldn't feel comfortable without having someone on the property at the same time as a paying guest. (Airbnb says credit card payments aren't finalized until "at least 24 hours" after check-in, to make sure guests are satisfied with their accommodations and to uphold host cancellation policies.)

But what convinces me our Airbnb adventure is headed in the right direction is Clarke's response to my wistful reminiscences about In-N-Out Burger, a legendary California fast-food chain we'd frequented before moving to the East Coast. Turns out there's a branch nearby — and, as a fellow addict, he'd be happy to make a delivery run our impromptu, al fresco dinner. Motel 6, eat your heart (or "double double" with fries) out.

Listings in 19,000 cities

Founded by twentysomething, San Francisco roommates who saw their blow-up mattresses as a way to score some extra cash, Airbnb has embraced the "sharing economy" and has grown far beyond its air-bed roots.

The short-term rental service has raised $120 million in funding and now has some 200,000 active listings in 19,000 cities and 192 countries, for everything from a $10-a-night couch in Brooklyn to a $1,250-a-night, five-bedroom villa near Bariloche, Argentina. (A recent revamp focuses on photo-centric "Wish Lists" curated by fellow users and such celebs as Airbnb investor Ashton Kutcher.)

Large U.S. cities are still major markets, but fewer than a quarter of its listings are located in the USA— and 57% are for an entire apartment, home or other rental unit, which include everything from Airstreams to houseboats.