Back in 2004, when I was a columnist for Red Herring, I wrote a piece about what would happen when reputation systems make their way into the world— that is, when they stop being things that we only consult in online transactions, and become things we can consult easily in real-world transactions. I talked about how they could jump-start car-sharing systems.

Today, I saw an article about RelayRides, a

person-to-person car-sharing service, which will be launching soon in Baltimore. Unlike fleet-based services—Zipcar, City CarShare, I-GO, and others—which maintain their own vehicles, RelayRides relies on individual car owners to supply the vehicles that other members will rent.

There are a couple other services like this, including Divvycar, but there seems to be a sense that these systems are ready to take off. So "why are peer-to-peer car-sharing services emerging now?"

Part of the answer might lie in the way online and offline services like Zipcar, Prosper, Netflix, and Kiva.org are training us to share our stuff—people are simply getting used to the idea. “‘Zip’ has become a verb to the point that we could ‘zip’ anything—they just happened to start it with cars. Close on their heels was Avelle (formerly Bag, Borrow Or Steal) and now SmartBike for bikes on demand. The next step seems to be a crowd-sourced version of Zipcar,” says Freed.

Another part of the answer might be found in our response to the ecological and economic crises Americans are facing. As Clark explains, “You just think of the number of cars on the road, and the resource that we have in our own communities is so massive… what the peer-to-peer model does is it really allows us to leverage that instead of starting from scratch and building our own fleet.”

From an individual’s perspective, peer-to-peer sharing is a means for owners to monetize their assets during times when they don’t require access to them. But peer-to-peer models can also be understood to utilize existing resources more efficiently—ultimately, to reduce the number of cars on the road—through shifted mentalities about ownership, the intelligent organization of information and, increasingly, through real-time technologies.

Since peer-based car-sharing companies don’t bear the overhead costs of owning and maintaining their own fleets, they don’t require the high utilization rates for vehicles that Zipcar and similar programs do—the result is comparatively fewer limitations for the size and scale of peer-to-peer operations.

Always satisfying for a futurist to see the future actually start to arrive.