Writer: Jean-Baptiste Rudelle, co-founder and CEO of Criteo

It has to be said that mobile devices have become a new trend. Currently, two-thirds of U.S. adults use smartphones. This year, the number of tablet users worldwide will exceed one billion. People spend even more time on mobile phones and laptops than they do on their bedtimes. With the popularity of mobile devices, people will spend more and more time on cross-screen devices, no wonder the U.S. will spend nearly $60 billion on digital advertising this year. Advertisers are pouring money into laptop, tablet and smartphone platforms in an effort to win consumers' attention and ultimately get a piece of the action when they buy.

"Digital advertising", also known as "Internet advertising" or "online advertising", is a complex area. In today's world, where people have countless devices and channels to access and buy consumer information, it's never easy for brands to successfully attract customers and increase sales. Digital advertising has never been as big as it is today. As people have more browsers and shopping choices and become more elusive, brands must ensure that consumers have a seamless and fluid experience when using cross-screen devices.

Next, I'll talk about four advertising strategies for brands to engage consumers and boost sales.

(Jean-Baptiste Rudelle, co-founder and CEO of Criteo)

The mobile side is unstoppable

Criteo regularly analyzes more than 1.4 billion online transactions to understand consumer spending behavior on cross-screen devices. Based on analytics data, Criteo publishes quarterly mobile e-commerce reports to help businesses measure their e-commerce success and help them plan ahead. Mobile e-commerce currently accounts for 35% of all mobile e-commerce transactions worldwide, according to the recently released Third Quarter 2015 Mobile E-Commerce Report.

That number is rising, while advertisers are spending more on mobile advertising. Why is mobile advertising expected to account for 72% of total digital advertising spending in the U.S. by 2019? Because advertisers want to meet the needs of consumers shopping on the mobile side, but also hope to attract the attention of consumers.

Businesses must adhere to a mobile-first e-commerce strategy. This means that businesses need to develop easy-to-use navigation and highly optimized mobile apps. Because mobile users use apps 86% of the time. Brands need to use this medium to attract consumers and increase conversion rates. Of course, it's also important to provide an intuitive, powerful and fascinating mobile web experience, as consumers often switch between multiple devices when shopping.

The desktop side is still strong

While mobile devices are the latest frontier in digital advertising, the desktop side is still a powerful tool for reaching consumers and helping them shop. Desktop search and display accounted for 38% ($19 billion) and 27% ($13.5 billion) of total digital advertising costs, respectively, in 2014, followed by mobile with $12.5 billion.

Computers, including laptops, are widely used in the corporate workplace today. As a result, many people will browse the web and shop on their office computers at lunchtime because of their personal needs. There is no doubt that mobile shopping is becoming more frequent, but desktop devices are still an important tool for consumers to shop. In addition, desktop advertising is critical in driving offline transactions. The auto industry, for example, contributes the second-largest share of U.S. digital advertising spending, after retail, but most of its transactions are done through agents.

Cross-screen trading cannot be ignored

Consumer buying involves a lot of equipment. Among them, consumers use a variety of devices before purchasing cross-screen transactions accounted for 40% of all e-commerce transactions. Some consumers start by browsing a product on a smartphone app during the day and then searching more on a tablet device at night, but end up using a laptop to make purchases at work. Digital advertisers should ensure a smooth, connected advertising experience when consumers switch devices.

While most mobile transactions are done via smartphones, tablets can't be ignored, especially when tablet companies release new products, such as Apple's new iPad Pro. Also, don't forget your smartwatch. While the smartwatch market is still in its infancy, consumers may soon be able to shop with their watches.

Attribution models deliver ROI

John Wanamaker, the father of American department stores, once famously said: "I know that half of my investment in advertising is useless, but the problem is that I don't know which half." "

Unlike traditional advertising, digital advertising is clearly measurable. However, because of the number of views, clicks, purchases, volumes, and other statistics involved, it can be complicated to calculate which ads translate into sales and by which devices.

To accurately measure the role of digital advertising in boosting sales, it is critical to have an experienced internal team and a reliable partner who keeps a close eye on market movements and delivers performance results. In the long run, attribution models will make tremendous progress in helping us understand the impact of online advertising on offline transactions, which is exactly the skills advertisers need to measure the effectiveness of their ads.

About Criteo

Criteo provides advertisers with large-scale, personalized performance ads. By measuring post-click sales conversion rates, Criteo makes ROI more transparent and easy to evaluate. Criteo is a fan of the Americas, Europe and Asia Pacific With 27 offices and more than 1,700 employees, it serves more than 9,250 advertisers worldwide and has direct relationships with more than 11,000 publishers worldwide. For more information, please visit www.criteo.com/cn.