NEW YORK ? A Facebook executive at the 2015 Mobile: IAB Marketplace said the social networking site?s ability to track mobile users across devices and gauge advertiser return on investment points to the need for delivering relevant and accurately measured messages in an era of cross-screen consumption.

The session, ?Cross-Screen Consumption: Where Mobile Video Comes to Life,? looked at how Facebook?s ?people-based marketing? approach lets publishers and brands explored the power of mobile video to reach consumers as they flock to popular video sites. The talk points to how with its rollout in recent months of ad targeting and measurement platforms such as Atlas, LiveRail and the Audience Network, Facebook?s advertising focus has shifted to providing ways for brands to more effectively target consumers.

 

?When a person goes into a store and buys a product, and checks out using their store card, which is connected to their phone number, we?re able to understand that that is the same person who saw an ad,? said Mark Trefgame, co-founder of LiveRail and product director for Facebook. ?We?re able to help advertisers understand the return on investment they are generating? 

The talk emphasized how Facebook?s marketing approach marks a fundamental shift in the way ads are targeted and measured.

?It?s a world where we use Facebook log-in to identify a unique user across all their devices and then tie back the delivering of that ad to a person,? Mr. Trefgame said. 

Atlas lets advertisers gauge the effectiveness of Facebook ads compared with other types of messaging. The Audience Network allows advertisers to target customers on external sites, using Facebook data. LiveRail lets publishers leverage video as an advertising option not only on Facebook?s site but on their own sites.

The talk highlighted how multiscreen content consumption on mobile makes it difficult to accurate measure a campaign?s effectiveness. Nearly one quarter of mobile consumers use at least three devices. The average consumer spends three hours daily on mobile, rapidly overtaking TV as the screen of choice.

A study of a high school student showed the subject switching devices 26 times in a day. 

?What that means for marketers is you can?t even assume that one device represents one person anymore,? Mr. Trefgame said. 

Demographic targeting is accurate only 59 percent of the time,  he said.

?They don?t even know accurately how many people they are reaching,? he said. 

The upside was even though you don?t accurately know how many people you are reaching, you actually could be doing better than you think. 

?You think your ads drove 10 sales but they actually drove 12. ?

Adding complexity to measuring effectiveness is that 94 percent of purchases still happen in stores. 

Forty percent of people begin browsing on one device and finish checkout on another.

?People based marketing is the way of the future,? he said. ?You will move to a world where people have not just two or three devices bit where they are always connected and they are using up to 10 different devices.?

Last week, Facebook announced it would leverage its Messenger chat window for one-to-one business-customer relations as the social networking site looked to position the application as a communications platform, partnering with Everlane, an online clothing site, and zulily, a flash-sale site. 

The move focused attention on the huge revenue windfall that messaging players would collect if efforts aimed at letting businesses connect with their best customers and fans on mobile were to win broad adoption.

Facebook?s cross-device approach helps provide a seamless marketing strategy in an increasingly multiple-screen world, Mr. Trefgame said. 

?It?s also able to capture that bridge between offline and online,? he said. ?So if we show an ad to someone, we?re able to understand that person very deeply.?