单选题Barter (易货贸易), the exchange of goods and services without the use of money, is not a new idea, but over the past decade, this type of transaction has been transformed into a sophisticated business practice. Today, the barter industry is composed of several thousand independent barter exchanges representing an estimated 100000 businesses worldwide turning over US $9 billion per annum. Through bartering, businesses in Asia, US, Australia and Europe have saved millions of dollars and were consistently able to move as much extra inventory (存货) as they want. But why is barter system back in style? There are many good reasons, but underlying them all is one fundamental business motivation: profit. Businesses can use barter to conserve cash, generate new business, and turn excess and idle inventory into useful products and services. Moreover, the rising inflation, job losses and the slowing economy have prompted an explosion of bartering where businesses as well as individuals can get what they want without spending any of their precious cash. The barter system enables traders to find new buyers of their products and services from the targeted universe of participants trading within a particular exchange. Barter exchanges are done by using a trade currency to measure the exchange of goods and services between businesses and individuals. Barter currency give people the ability to purchase a future good or service that equals the amount of barter currency they own. This method allows businesses as well as individuals to get the things they need without having to expend additional money. Instead, they can use the things they no longer need or want to get the things they do need. Bartering can also be used by businesses that are seasonal in nature such as resort hotels. A bartered hotel room is more cost effective than an empty one. Bartering thus allows businesses to capitalize on unproductive assets and spare capacity. With a large exchange, it is possible to barter pretty much anything. There are exchange markets and online auctions that allow businesses to sell or trade their inventory or to purchase items that they want such as: barterplant.com, a free online community for trading items, services, and knowledge; swaptree.com, which specializes in trading books, video games, DVDs, and music and swapstyle.com, which allows members to swap clothes, shoes, cosmetics, and accessories. Although cash still in control, barter industry experts think, there is more room for barter. They predict that the globalization of barter over the next decade will be powered by a universal barter currency. Having a barter currency, which does not go up and down depending on the stability or instability of the world markets, means that the future prospects of the barter industry look pretty bright.
单选题
What can we learn about barter from the passage?