As Revenue Stagnates, Yahoo Bets on Homegrown Ad Tech

Two years into the Marissa Mayer reign at Yahoo, the Internet pioneer is still struggling to find a comprehensive strategy for its core online advertising business. A new effort to build an ad exchange with in-house technology could mark a turning point for Yahoo, but it’s not yet clear if the long-troubled company can make it work.

Unlike its rivals, Yahoo has for years focused on super-premium display advertising on Yahoo-branded sites, shunning the industry-wide shift toward automated ad exchanges that can serve up targeted ads across the thousands of websites.

In January, Ms. Mayer signaled that was changing with the announcement of Yahoo Advertising, which includes an ad exchange designed to tap into deep wells of user data to help advertisers find customers all across the Internet.