Text 2

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 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. 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