The exchanges detailed in this article in the New York Times involve money, which is frowned upon by some who think everything neighborly should be given away free. But barter as well as monetary exchange i’s traditional neighborhood behavior. Hiring the neighbor’s kid to mow the lawn or babysit, buying eggs from someone up the hill. In fact, small-scale interdependence like this does build a sense of community. The sites mentioned include SnapGoods, NeighborGoods, and ShareSomeSugar. Here’s a bit from the article:

Paul J. Zak, director of the Center for Neuroeconomics Studies at Claremont Graduate University in California, says that participating in a community like SnapGoods, Kickstarter, Groupon or Airbnb can ease social isolation and flesh out our network of friends.

“There is an underlying notion that if I rent my things in my house, I get to meet my neighbor, and if I’m walking the goods over, I get to meet them in person,” he says. “We’re drawing on a desire in a fast-paced world to still have real connections to a community.”

Ping – Renting Out Home Belongings Over the Internet – NYTimes.com.