“The holy grails of consumerism are convenience and choice,” says Rachel Botsman, co-author of the forthcoming book, “What’s Mine Is Yours: The Rise of Collaborative Consumption.” “This is not the end of the old consumer way. But they could sit side by side. Peer-to-peer could become the default way to share.”

There’s much evidence that this is already happening. Do-it-yourself home improvers can borrow tools for a weekend project, and hobbyist campers can rent equipment per trip, rather than splurge on all-new gear. Travelers looking for inexpensive accommodations can spend the night in someone’s spare bedroom for a fraction of the cost of a hotel room. For people who lend their stuff, it’s a way to make extra money on possessions that are gathering dust.

“My Roomba is on track to pay for itself,” says Luke Tucker, 31, a software engineer who rented me his robotic vacuum cleaner through SnapGoods.

But some experts think that there may be something bigger than thriftiness at play. These services may be gaining popularity because they reinforce a sense of community.

“It turns out to actually be a good way to meet my neighbors,” says Mr. Tucker, who also lists a jigsaw, a digital camera and a wireless keyboard for rent on SnapGoods.

Image SnapGoods lets people rent out belongings for small fees. Ron J. Williams, left, and John Goodwin are co-founders. Credit... Ruby Washington/The New York Times

Charlis Floyd, a 22-year-old student, and Nema Williams, a 30-year-old comedian, who rent out their spare bedroom in Brooklyn on Airbnb, say that while the extra income helps  as any little bit does these days  they’re much more interested in the revolving cast of characters they meet.