For example, Couch Surfing, where people opt into a global network and agree to let strangers sleep on their couch for a night in exchange for the right to sleep on other strangers' couches all over the world.
Some might look at this as a better use of available resources, but I think that misses the point a bit. It seems unlikely that a website that allowed people to rent out their couches for $5 a night would be far less popular.
Like organ donations and amateur athletics, hospitality is a sphere in which people feel uncomfortable involving money, even if exchanges involving money would improve overall welfare. Because couch surfing is potentially quite dangerous, though, this anti-money impluse might make a lot of sense; people are more willing to trust a stranger who is willing to trust strangers than a stranger with $5.
Charity as a substitute for reputation: evidence from an online marketplace, Daniel W. Elfenbien, Ray Fisman, Brian McManus, Review of Economic Studies, forthcoming.
Consumers respond positively to products tied to charity, particularly from sellers that
are relatively new and hence have limited alternative means for assuring quality. We
establish this result using data from a diverse group of eBay sellers who “experiment”
with charity by varying the presence of a donation in a set of otherwise matched product
listings. Most of charity’s benefits accrue to sellers without extensive eBay histories.
Consistent with charity serving as a quality signal, we find fewer customer complaints
among charity-intensive sellers.
(Thanks to Peter Jaworski for couch surfing)