Bellack said Google's big engineering challenge in making publishers' custom native formats available on exchanges was separating the assets of an advertiser's creative from the ad spec as defined by the publisher.
To get there, Google introduced two standard native templates that any publisher wanting to sell programmatically can use: one for content-driven marketing and one for app install ads. The publisher can customize these templates according to the look and feel of their properties.
From an advertiser's perspective, the process for buying native ads is substantially different from transacting on a banner ad. Rather than upload pre-defined ad creatives for delivery to familiar banner-sized boxes, a buyer instead provides a collection of ad assets: champion image, headline, body copy and so on. Google then assembles and serves the ad according to the publisher's user experience.
"As an advertiser you need to think about assets that will work in a range of presentations," Bellack said. "We had to build that tech that could have those two things [the publisher spec and the creative assets] be separated."
Google is not the first to tackle this challenge. Other companies offering native programmatic ads include Facebook, Twitter, Yahoo and a group of ad tech specialists including Sharethrough, TripleLift and Bidtellect.
USA Today is among the publishers already leveraging DFP to serve native ads, a capability introduced earlier this year. In the absence of a Google programmatic sales channel, the company has partnered with Sharethrough to monetize that inventory.
Chris Pirrone, general manager at USA Today Sports Media Group, was briefed recently on Google's new push into exchange-traded native ads.
"I think it's impressive, what they've built," Pirrone said. "Programmatic has always been about defining ad slots and therefore allowing everyone to transact on standard native formats and sizes. Native doesn't work that way. I think initially it was outside Google's comfort zone, and I'm impressed that they pushed it through. It lends credence to how important native is."
From the buyer perspective, Google's move is likely to bring a new type of advertiser into the programmatic native fray, according to Michael Collins, CEO of mobile DSP Adelphic.
"Given Google's scale, it can help accelerate adoption of native inventory by brands," he said. "The performance is great. Not just the click through rate, but the post-click engagement is very strong. That said, the adoption we're seeing from brands as opposed to performance advertisers hasn't really taken off yet."
Separately, Google has introduced programmatic support for video in mobile interstitial placements in apps.
"It's a format that consumers are comfortable with once they're in the world of an interstitial in an app. As we know there's a lot of demand," Bellack said.