Four years after Pam Omidyar’s personal mania for collecting Pez dispensers created eBay, terms such as “frictionless marketplaces” and “barter economy” are being casually bruited about. Economists have had fun exploring the implications for on-line auctioneers and for consumers. But, what if you’re a real-life manufacturer of honest-to-goodness products that everyone is suddenly so eager to swap, discount, hoard, arbitrage, and generally wheel-and-deal? How do you plan your business in a world where your products just get passed from one consumer to the next, instead of getting thrown away?

The answer begins in, of all places, the used-car lot.

Cars serve as such a good analogy because car makers have, for decades, had to deal with the fact that their products may pass through so many hands before they finally die of exhaustion. Car makers have learned a couple of basic things:

 Having used cars expands the total market for automobiles because people who couldn’t afford a brand spanking new car can easily purchase a used one. In addition, people who are leery of laying down $40,000 for a new BMW might do it anyway if they know they can unload the car in the unlikely event that that promotion and raise don’t come through.

 But having used cars also can diminish the market for new cars. Why buy a sparkly new car that will lose 20% of its value the second you drive it off the dealer lot, when you can buy a used car for so much less?

It’s too early to say how these seemingly contradictory forces will play out in other markets, and results are sure to vary by industry. But looking a little deeper into the used-car market suggests a handful of principles that manufacturers of other goods should at least consider adopting today, against the day when the used market becomes so big on-line that it changes the dynamics of their markets:

INNOVATE. Car makers have, for decades, added little touches such as fins or heated seats as a way of trying to make their products behave like fashion and push people to want the latest and greatest. And, sure enough, there are lots of people who buy a new car every year or two and trade in the old one. I personally feel more comfortable buying the latest Palm Pilot or Nokia phone, because I can easily unload it for a decent price at an auction site (and get a better and cheaper one). And I’m sure innovation will increasingly drive purchases of other goods. People will decide they need the latest features and gizmos, even for items such as dolls that aren’t ordinarily associated with innovation, and they’ll be confident that they can trade the items in when it’s time to move on.

INVEST IN YOUR BRAND. Brands are crucial in confusing environments, when customers need a shorthand way of figuring out whom to trust—and markets for used products are inherently confusing. The brand has to be especially strong because you won’t control how your product is represented when it is resold; you’ll be at the mercy of whomever bought the product from you in the first place. The brand also has to extend to the resale value of the product, because that will become a more important factor for your customers. Honda, Toyota, and Mercedes, for instance, have long sold cars based on the fact that they hold their value so well.

Be prepared to charge a premium in the primary market for your products if you can show that they hold their value in the secondary market.

CREATE AN AFTER-MARKET CHANNEL. Having your products sold and resold presents an opportunity for you to sell new kinds of services for them. Depending on the type of product you sell, that service could be: certificates of authenticity, repair, financing, or a host of other possibilities. Every car dealer knows there is real money to be made on service, warranties, and accessories for used cars.

Financing, in particular, will become easier to figure out over time as the markets for various products become more liquid. At the moment, it may be hard to determine the value of an antique armoire, but as more are sold it’ll become relatively easy to come up with a close approximation of the price it should command. Car makers have taken advantage of this sort of data, so they know just what financing deal they can set for each car based on its condition, the number of miles driven, and so on. Car dealers have also used the information about prices to produce a whole variety of leasing and repurchase deals.

GLOBALIZE. As pressure builds from competitors and, now, secondary-market sources, it only makes sense to widen your marketplace. The used market could well broaden the demand for your products because it will put their prices within the reach of those who couldn’t afford them new.

A warning: Globalization may be complicated. You may need to target older products for less-advanced nations, or to come up with several tiers aimed at different parts of different types of countries.

TRY “RISK SHIFTING.” Car manufacturers have learned to overcome resistance to rising prices and new products through leasing and rental programs that transfer some of the risk of trial and purchase back to the manufacturers. Car manufacturers have an out, of course, because they can turn to the used market when the cars are returned to them. Many other types of manufacturers will soon have similar recourse, so it only makes sense to look for other markets where risk-shifting approaches could apply.

I suppose there’s actually one more way that manufacturers outside the car industry could draw on Detroit’s experience. They could start referring to used goods as “previously owned.” But let’s not do that. Please.

Agrawal is a management consultant based in Chicago. He can be reached at sagrawal_99@worldnet.att.net.