An old saying has it that half of all advertising budgets are wasted—the trouble is, no one knows which half. In the internet age, at least in theory, this fraction can be much reduced. By watching what people search for, click on and say online, companies can aim “behavioural” ads at those most likely to buy.

    In the past couple of weeks a quarrel has illustrated the value to advertisers of such fine-grained information: Should advertisers assume that people are happy to be tracked and sent behavioural ads? Or should they have explicit permission?

    In December 2010 America’s Federal Trade Commission (FTC) proposed adding a “do not track” (DNT) option to internet browsers, so that users could tell advertisers that they did not want to be followed. Microsoft’s Internet Explorer and Apple’s Safari both offer DNT; Google’s Chrome is due to do so this year. In February the FTC and the Digital Advertising Alliance (DAA) agreed that the industry would get cracking on responding to DNT requests.

    On May 31st Microsoft set off the row. It said that Internet Explorer 10, the version due to appear Windows 8, would have DNT as a default.

    Advertisers are not horrified. Human nature being what it is, most people stick with default settings. Few switch DNF on now, but if tracking is off it will stay off. Bob Liodice, the chief executive of the Association of National Advertisers, says consumers will be worse off if the industry cannot collect information about their preferences. People will not get fewer ads, he says. “They’ll get less meaningful, less targeted ads.”

    It is not yet clear how advertisers will respond. Getting a DNT signal does not oblige anyone to stop tracking, although some companies have promised to do so. Unable to tell whether someone really objects to behavioural ads or whether they are sticking with Microsoft’s default, some may ignore a DNT signal and press on anyway.

    Also unclear is why Microsoft has gone it alone. After all, it has an ad business too, which it says will comply with DNT requests, though it is still working out how. If it is trying to upset Google, which relies almost wholly on advertising, it has chosen an indirect method: There is no guarantee that DNT by default will become the norm. DNT does not seem an obviously huge selling point for Windows 8—though the firm has compared some of its other products favourably with Google’s on that count before. Brendon Lynch, Microsoft’s chief privacy officer, blogged: “We believe consumers should have more control.” Could it really be that simple?

答案精析：根据人名Bob Liodice可定位到第五段第四句。定位句中鲍勃指出，如果广告产业不能收集用户偏好信息，那么用户体验会更糟（worse off），而投放的广告不会变少，反而会更没有意义，更没有针对性（less meaningful, less targeted），即用户会接收到无目的、没有针对性的广告，由此可以判断出“请勿跟踪”设为默认对消费者的体验无益，选C。

错项排除：原文没有提及垃圾广告这一概念，因此A排除。本段第一句提到广告商的态度是horrified（惊慌失措），而且根据文意也可推测广告商会受到较大的影响，因此B错误。而D偏离文章主题，且在文中未提及，故排除。

长难句分析：Bob Liodice, the chief executive of the Association of National Advertisers, says consumers will be worse off if the industry cannot collect information about their preferences.

本句主干为Bob Liodice… says consumers…，为主谓宾结构，其中宾语是省略that引导的宾语从句。the chief executive of the Association of National Advertisers是Bob Liodice的同位语。宾语从句中嵌套了if引导的条件状语从句。

句意为：美国广告主协会会长鲍勃·雷奥戴斯说，如果广告商不能收集有关用户偏好的信息,那么这对于消费者来说将更为不利。