Ride- and home-sharing startups shaking up the world are old concepts getting new life, founders of two prominent ventures told an "ideas conference" Tuesday.

"We didn't invent anything new," co-founder Joe Gebbia said of Airbnb during a candid presentation at the prestigious annual TED gathering in Vancouver.

"Hospitality has been around forever."

During a separate TED talk, Uber co-founder Travis Kalanick described Uber as a modern day spin on the "Jitney," a ride-sharing trend that rocketed after being launched in California in 1914 but which was crushed under the weight of regulation in subsequent years.

"It turns out there was an Uber way before Uber," Kalanick said during an on-stage talk.

"If it had survived, the future of transportation would probably be here already."

The name "Jitney" came from a slang reference to a US five-cent coin, which is what a car dealer in Los Angeles who noticed crowds waiting for trollies decided to charge people to take them where they wanted to go.

Within a year the trend spread to other US cities, to the chagrin of powerful trolley operators, Kalanick said, drawing a parallel to opposition that the smartphone-based ride-sharing service has gotten from the taxi industry.

The trolley industry successfully lobbied for regulation of the Jitney, winning rules such as mandating two drivers per car; long hours behind wheels, and even back seat lighting to discourage the "pernicious" trend of couples "spooning," Kalanick quipped.

He drew a connection between the Jitney being regulated out of existence and rocketing sales of personal automobiles that shaped modern lifestyles and by extension, bred woes such as traffic congestion and pollution from exhaust fumes.

"When we started Uber in 2010 we just want to push a button and get a ride; we didn't have any grand ambitions," Kalanick said.

"Well, it turned out that a lot of people wanted to just push a button and get a ride."

San Francisco-based Uber has grown from 40 people at its start to 6,500 employees now, he noted.

In China alone, there are 15 million UberPOOL trips monthly, and exponential growth is also being seen in Los Angeles, according to Kalanick.

UberPOOL lets riders heading for common destinations split the cost of trips.

He saw self-driving cars becoming part of the ride-sharing equation, but perhaps not for a decade or two.

"It is going to be a long transition, and they will work well in some places and not in others," Kalanick said of seld-driving cars.

"This is a world that is going to exist, and for good reason."

He listed Apple, Google, Tesla and major auto makers among the companies working on autonomous vehicles.

- 'Stranger danger' -

Airbnb co-founder Gebbia recalled holding a yard sale a day after graduating college, only to let a seemingly friendly fellow who bought some of his art crash in his living room for a night.

He recounted waking up in the middle of the night and locking his bedroom door to make sure he would be safe from someone he didn't know.

That sense of "stranger-danger" typically learned as children was among challenges that Airbnb had to surmount to get people to open doors for travelers, according to Gebbia.

"We have been taught since we were kids that strangers equal danger," Gebbia said.

"We had to build Olympic-size trust between people who never met."

Airbnb tackled the trust challenge with a website that let hosts and aspiring guests learn a bit about one another, and to build reputations in the form of reviews.

"Things have been going pretty well," Gebbia said, noting there have been incidents such as unsanctioned parties leaving homes wrecked and customers left standing in the rain when lodging didn't come through.

"Thankfully, out of the 123 million nights we have seen hosted, less than a fraction of a percent have been problematic. When trust works out right, it can be absolutely magical."

A powerful appeal of the "sharing economy" is about making traditional business transactions into opportunities to share cultures, experiences and local culture as well, according to Gebbia.

"People share a part of themselves, and that changes everything," Gebbia said.

"I see a future of shared cities that bring us community and connection instead of isolation and separation."