SHOPPERS on Black Friday, the traditional start of the holiday shopping season in America, which falls on November 27th this year, are notoriously aggressive. Some even start queuing outside stores before dawn to be the first to lay their hands on heavily discounted merchandise. Last year berserk bargain-hunters in the suburbs of New York City trampled a WalMart employee to death. Despite the frenzy at many stores, however, the recession appears to have accelerated the pace at which shoppers are abandoning bricks and mortar in favour of online retailers- e-tailers, in the jargon. So this year Black Friday (so named because it is supposed to put shops into profit for the year) also marks the start of many conventional retailers’ attempts to regain the initiative.E-commerce holds particular appeal in straitened times as it enables people to compare prices across retailers quickly and easily. Buyers can sometimes avoid local sales taxes online, and shipping is often free. No wonder, then, that online shopping continues to grow even as the offline sort shrinks. In 2008 retail sales grew by a feeble 1% in America and are expected to decline by more than 3% this year, according to the National Retail Federation, a trade body. In contrast, online sales grew by 13% in 2008 to over $141 billion and are predicted to grow by 11% in 2009, according to Forrester, a consultancy.Online-only shopping sites such as Amazon and eBay, two e-commerce giants, have thrived in the downturn. Amazon’s sales rose to around $ 5.5 billion in the third quarter of the year. up by almost 30% from a year before. Listings, chiefly from commercial vendors, have surged so rapidly on eBay that its website briefly crashed on November 21st. The range of items available online is also growing. Amazon has started selling groceries. Consumer-goods companies such as Procter & Gamble (P & G) are encouraging the sale of things like nappies (diapers) and laundry detergent online. At the opposite extreme, the internet is also being used to sell luxury goods. Fabergé, a defunct jewellery-maker known for its gem-encrusted eggs, relaunched in September. It will not open any shops but will instead operate only online.The shift in spending to the internet is good news for companies like P & G that lack retail outlets of their own. But it is a big concern for brick-and-mortar retailers, whose prices are often higher than those of e-tailers, since they must bear the extra expense of running stores. Happily, however, conventional retailers are in a better position to fight back than last year, when overstocking forced them to resort to ruinous discounting. Inventories are about 15% lower this year. Some big retailers, such as Saks and Target, have recently reported rising revenues and margins.The concept of " mulichannel" shopping, where people can buy the same items from the same retailer in several different ways online, via their mobile phones and in shops—is gaining ground, and retailers are trying to encourage users of one channel to try another. Growing onlinc traffic may actually increase sales in stores too. According to a spokesman for Macy’s, a departmentstore chain, every dollar a consumer spends online with Macy’s leads to $ 5.70 in spending at a Macy’s store within ten days, because consumers learn about other products online and come into stores to look them over before buying them. Many online retailers offer tools that let people locate the nearest outlet that has a given item in stock.Retailers are also trying to make shopping seem fun and exciting to counteract the economic gloom. One common tactic is to set up " pop-up" stores, which appear for a short time before vanishing again, to foster a sense of novelty and urgency. Following the lead of many bricks-and-mortar outfits, eBay recently launched a pop-up in New York where customers could inspect items before ordering them from kiosks. "Pop-up" stores can help to fight against economic gloom because they（）

A. appear for a short time and then vanish.
B. attract and urge consumers to make prompt purchase.
C. cut the extra expense of running stores.
D. are proved effective by online retailers.