AT two inches wide and one-third of an inch tall, a display ad shown on a smartphone isn’t much of a canvas for a creative marketer seeking to promote a product or service.

2英寸宽，1/3英寸高，智能手机上的这种广告展示并不能成为有创意的销售人员用来推销产品或服务的画布。

That’s one reason smartphones are not working well as a medium for many advertisers. The evidence is telling: advertisers are willing to pay much more to reach a thousand pairs of eyes gazingupon a computer or tablet than a thousand pairs looking at a smartphone screen.

这是智能手机并非广告客户的良好媒介的一个原因。证据显示，广告客户愿意花多得多的钱吸引1000名来自电脑或平板的用户，而非同样数量来自智能手机的用户。

“Size absolutely does matter,” says Christine Chen, director of communication strategy at Goodby Silverstein & Partners, an ad agency in San Francisco. “If you look at the real estate¹ available on a smartphone, it’s really sad compared to not just banner ads on the Web, but also to TV, print and outdoor advertising².”

旧金山广告代理Goodby Silverstein & Partners的沟通策略总监克里斯汀·陈说：“尺寸绝对是个大问题。智能手机上的房产广告看起来远逊网上的横幅广告，以及电视、纸质和户外广告。”

Size isn’t the only problem. Advertisers are also limited by what they can find out about smartphone users. It’s not technically³ possible to use cookies with smartphone apps the way it is with a browser⁴. On the Web, publishers typically record users’ actions so that advertisers can make an educated guess about a user’s identity and interests.

尺寸并非唯一问题。广告客户能获取的智能手机用户的信息也很有限。从技术角度看，智能手机应用无法像浏览器一样使用cookie。网站发布者通常会记录用户的行为，这样广告客户就能更好的猜测用户的身份和兴趣。

“What makes Web ads so attractive to advertisers is the ability to track actions and optimize⁵ accordingly,” Ms. Chen says. Because a smartphone cannot use the same technology, she says, “your ability to track and optimize is much more blunt, or in some cases nonexistent.”

陈女士指出：“网页广告如此吸引广告客户之处在于它能追踪用户行为并据此进行优化。”她还表示，由于智能手机无法使用同样的技术，“追踪和优化的能力大为减弱，某些情况下完全没有。”

These limitations depress demand for smartphone ads and lead to low prices. A banner ad on a Web page that costs $3 to $5 for every thousand impressions may cost only 75 cents or $1 for a thousand impressions on a smartphone, Ms. Chen says.

这些限制使智能手机广告的需求不高，价格也较低。网页上的一条横幅广告，每千次有效展示的价格为3至5美元，而智能手机上可能只有75美分至1美元。

Another reason advertisers don’t value smartphone ads highly is that users tend to lack a receptive mindset when using their phones. “It’s an activity you do for a short burst of time,” Ms. Chen says. “It’s very functional⁶.” That is not a good time to try to make users stop what they are doing and give their attention to an advertiser’s message.

广告客户不看好智能手机广告的另一原因是用户在使用手机时接受信息的思维模式不足。陈女士指出：“使用手机是一种短时行为，目的性非常强。”这并不是一个让用户停下手上的事情关注广告信息的好时间。