Google yesterday became the first large online ad network to charge clients only if their adverts¹ have been seen, in a radical² shake-up of pricing that affects more than 2m sites in its display advertising³ network.

谷歌(Google)昨日宣布，广告只有被浏览才收取费用，由此成为业内首家作出如此承诺的大型网络公司。谷歌此举将会给它的广告定价带来巨大影响，波及到它广告展示网络中的逾200万家网站。

“If you are an advertiser and a human being didn’t see your ad, then frankly⁴ nothing else matters,” said Neal Mohan, Google’s vice-president of display advertising products.

谷歌展示广告业务副总裁尼尔•莫汉(Neal Mohan)表示：“如果用户没看到广告商发布的广告，坦白说，广告就失去了意义。如果没人看你的广告，广告商为什么要付钱？”

“If you are a marketer, why pay if a human being did not see the ad?”

“广告没被看到的问题”，一直以来都在困扰着总值达1170亿美元的全球在线广告业。

The problem of adverts that do not get seen has plagued the $117bn global online advertising industry.

据估计，广告商购买的多达一半的数字广告根本没人浏览，还有一大部分广告只有当网络用户向下滚动到网页底部时才会被看到。数字广告尽管发展迅猛，但仍然只占广告总开支的五分之一左右。莫汉表示，帮助广告商衡量广告宣传的有效性，才能保证广告商增加投入。

It is estimated that as many as half of the digital ads that marketers buy are not seen at all, with a large portion only being viewed if a website user scrolls⁵ all the way down to the bottom of a web page. Despite explosive growth rates, digital advertising still accounts for about only a fifth of the overall spending on marketing⁶, and Mr Mohan said helping⁷ marketers measure the effectiveness of ad campaigns would secure more spending.

电视广告也面临这一问题。广告商可以追踪其投放的广告是否在电视上播放，却很难确定人们是否在看广告，还是趁广告时段跑到厨房弄吃的。

This problem is also shared by television adverts. On TV, marketers can track whether an ad is shown but it is difficult to find out whether or not someone actually saw a commercial or ran to the kitchen for a snack.

为了开发新产品，谷歌使用了一种新型行业标准，即如果一则广告的50%以上出现在电脑屏幕上，并至少持续一秒，才能被视为这则广告是“可视”的。谷歌自主开发了相关技术，不仅能测定广告是否呈现，而且还能找出广告的哪一部分出现在电脑屏幕上。

To develop its new product, Google used an emerging industry benchmark that only considers an ad “viewable” if more than 50 per cent of it is visible on the screen for one second or longer. Google developed its own technologies to detect not only whether an ad is visible but also what portion of it can be seen on the screen.

谷歌没有对哪些在线广告属于“不可视”范畴发表置评，但它强调，消除“不可视”广告会导致广告产品供应受限，因而广告费用有可能上涨。

Google would not comment on what portion of ads on its networks are not “viewable” but noted⁸ that prices are likely to rise as the supply of ad inventory⁹ is constricted¹⁰ by the ruling out of “non-viewable” ads.

广告商同时还面临数字广告方面的其他问题，如大量出现的在线广告欺诈行为，这是指诈骗者侵入其他用户电脑，并伪造对某些网页的浏览或对广告的点击。