In this series, the 2016 Year in Preview, Digiday’s reporters and editors are looking at the major trends of 2016. Download all 10 installments here.

The classic example of the “creepy” ad is almost quaint these days: The pair of shoes you browsed once that now shows up on every website you visit. Adorable. In 2016 targeted advertising will get more sophisticated thanks to the reams of data sucked in by platforms like Google and Facebook.

The question of how far to go with targeting will be one of the most important issues facing the industry in 2016. Last year, arguably the big issue was ad blocking, but the rise of anti-ad software is deeply related to privacy.

“There is a fine line between what advertisers are capable of doing and what is right to do based on the consumer reaction and consumer expectation,” said Richard Guest, president of Tribal Worldwide’s North America operations.

Highly personalized tactics are ever tempting for advertisers. On Facebook, you can create 1,000 different ads for 1,000 hyper-targeted audiences of different ages and family makeup and means. Advertisers can deploy cross-device sequential messaging that can turn ads into precision-guided, location-based marketing missiles. The ads are based on data collected everywhere – from Facebook, the Web, mobile devices, credit card histories, in-store purchases. On Pinterest, you could target mothers of six-month-olds, 1-year-olds, 2-year olds, toddlers or teens.

“There’s a huge difference between the buying habits of new moms versus moms of six months plus versus moms of one-year-olds,” said a digital ad executive who works closely with Pinterest. “What they’re able to do in terms of driving qualitative output for brands to make real business decisions is massive.”

On Twitter, campaigns have been addressed with people’s names on them.

Then there’s Google, with all the new ways to target ads, the search giant perhaps has the best historic information on everything everyone has ever looked for online. Google may have to cave to the growing pressure to make more use of search to target ads, which had been almost unthinkable in the past, according to numerous marketing technology insiders.

Even Snapchat, the app designed on the premise of disappearing data, is now building an ad business. The app started without wanting to do advertising, but then came around to broad non-targeted campaigns. To grow, many advertisers expect it is only a matter of time before the company embraces more developed methods of customizing ads for specific audiences.

“At some point, they’ll have to open the floodgates and say they’re open for business, here,” said one digital media buying executive. “It happened at Google, Yahoo and Facebook.”

The rise of ad blockers has brought the issue of “good” ads to the forefront. The industry has long relied on self-regulation and on the arbitrary line of not using “personally identifiable information” for targeting. In November, the Digital Advertising Alliance created the first opt-out mechanism for cross-device tracking, which lets consumers stop a computer or phone from receiving ads based on data collected about their habits on other devices.

Still, the ad alliance also has an opt-out website for behavioral tracking, and these measures are meant to head off further scrutiny by watchdogs and governments outside the ad industry.

Of course, self-regulation hardly keeps all the heat off advertisers and Internet companies. In 2015, Facebook faced intense pressure from European regulators over the types of data it stores about users and non-users. This year, Verizon bought AOL and is building one of the strongest data-based ad platforms on the planet. It will mix AOL’s ad technology with Verizon’s customer data — tens of millions of families and their billing information mixed with media habits mixed with device identifications.

The industry’s bet is, besides professional privacy advocates, not many real people will be bothered.

Did you enjoy this essay? There are nine more just like it as part of Digiday’s Year in Preview series. The full series is available for download in one PDF – sign up here to get your copy.

  • LinkedIn Icon