Looking Beyond the Facebook / Google Duopoly

Google and Facebook, taken together, will account for about 63% of US digital ad revenues this year—and their share is growing.

With the duopoly taking in about two-thirds of US digital ad revenues, that leaves around a third of the market for every other firm to compete for. Most of that third is taken up by the long tail: Well over half of net US digital ad revenues at companies other than Facebook or Google go to firms outside the handful of major ad companies tracked by eMarketer.

That share is falling, however. In other words, not only are Facebook and Google increasing their portion of the market, the remaining "Big 8" publishers are also gaining, meaning that, each year, less of the remainder is left for every other publisher on the market.

Oath and Microsoft are tied as the largest individual digital ad firms outside the duopoly, with each expected to take 11.8% of the nonduopoly market this year. Third-place Amazon is far behind, with 5.4%, but will close the gap significantly by 2019, even as Twitter will lose share—and its No. 4 ranking—to Snapchat.

The data in this article is drawn from eMarketer's new report, "Beyond the Duopoly: Exploring Digital Advertising Outside Google and Facebook." Aside from breaking down spending patterns, the report identifies opportunities and challenges for "nonduopoly" platforms. eMarketer PRO subscribers can access the full report here. Nonsubscribers can learn more here.

In the latest episode of "Behind the Numbers," eMarketer analysts Nicole Perrin and Debra Aho Williamson further discuss how ad spending is flowing to all those publishers and platforms that aren't Google and Facebook.