Dive Brief:

• Walmart is slowly and quietly growing its digital advertising business to become a more serious player, according to a report in Digiday. The publication didn't speak to Walmart executives, but cited several agency heads who pointed to brands' growing interest in the retailer as an advertising vehicle. Walmart isn't likely to threaten Google or Facebook, but it might be able to gain an edge over e-commerce competitor Amazon, which is sometimes propped up as the next significant challenger to the Facebook-Google duopoly. 
• Walmart's advantage rests in its ability to combine offline and online activities with its opted-in shoppers, Digiday said, and one agency executive called its in-store data a "secret sauce." The consumer product retailer has 140 million shoppers at its 5,000 brick-and-mortar stores, and is more often providing insertion order media buys and programmatic display inventory via Walmart Exchange, a media network it rolled out in 2014. 
• Walmart is offering banner ads, search, product listing and native ad formats. Similar to Amazon, Walmart offers ads that appear at the point of sale. While people research potential purchases on platforms like Google, ads that get served on e-commerce websites like Amazon and Walmart are an easy click away from the buy conversion.

Dive Insight:

Marketers are desperate for a new digital advertising platform that can edge into Google and Facebook's massive share of the market. In March, eMarketer forecast that Google and Facebook will together command 51.6% of digital display advertising this year, leaving brands with few alternatives, even as the duopoly has been mired in brand safety and measurement issues.

Earlier this year, WPP CEO Martin Sorrell singled out Amazon as the platform to keep an eye in the race to win over more ad dollars, but Walmart may be a dark horse with some serious legs. While it's unlikely that Walmart will grow to stand shoulder-to-shoulder with Facebook or Google from an advertising standpoint, the data it retains on its physical and online shoppers are highly coveted by marketers and could help brands better bridge the gap between digital and in-store shopping.

If Walmart won't dominate digital advertising, it might better serve a specific segment of retail marketers looking to more sharply target and specialize their online advertising strategies to reach and convert customers.