Resource sharing, it turns out, can get pretty personal. Not only are occasional drivers sharing rental cars via car sharing services such as Zipcar and Buzzcar, but they're also sharing their own cars – and even their beds -- with strangers.

“It’s all there,” said Robin Chase, founder and former CEO of Zipcar, during GreenBiz's three-day VERGE DC conference last week. In other words, many different types of resources are used only part time, and could be made available to more people the rest of the time.  

All that sharing can not only save money, but also natural resources. And while some companies profit on excess, others – both organizations and private individuals -- can profit from finding ways to use existing products to their full capacity, Chase said.

Zipcar, the world’s largest vehicle-sharing company, allows users to search an inventory of its vehicles parked in various locations, which they can reserve and then access with an electronic card key.

In San Francisco, after a $25 application fee, users pay $60 a year, according to the company’s website. A search of vehicles in the city’s Mission District showed dozens ranging from $7.75 an hour to $12 an hour, including gas and insurance.

After 11 years, 650,000 Zipcar users are sharing 9,000 cars, Chase said. That means less gas use, fewer emissions, fewer filled parking spaces and fewer cars being bought, she said. Some colleges that have partnered with the company have been able to build fewer parking garages than they expected, and users think more about ways to get around without a car.

“When you pay by the hour, by the day, you drive 80 percent less,” said Chase, who is also working on new ventures. Eight months ago, she started Buzzcar in France, where owners put their personal vehicles up for rent.

Personal-vehicle sharing also is available in the United States, such as through RelayRides. In an online chat room during the conference, Chase acknowledged skepticism that some would let others use their personal cars. But Zipcar also had its naysayers, she said, adding that users on both ends are more practical than they're given credit for.

“If you can pay for all your gas, or your insurance, or afford off-street parking by renting your car for a couple days a month, why wouldn't you?” she wrote.

After all, plenty of users have shown they're willing to let strangers share space that's arguably even more personal. Companies like CouchSurfing enable users to temporarily share their residences with short-term visitors. Users can put up profiles of themselves, the residences and ratings from others. CouchSurfing's 1.2 million users in 237 countries far surpass longstanding hotel chains, Chase pointed out.

"Bed sharing is more impressive," she added.

Photo of Mini Convertible courtesy of Zipcar; photo of Robin Chase from VERGE DC taken by Goodwin Ogbuehi for GreenBiz Group.