Technology has prompted tremendous change in the advertising industry—change that would have been inconceivable even a decade ago. People are accessing, consuming, and sharing content in more varied ways than ever, and marketers have scores of new opportunities to understand, reach, and engage with consumers. But at the same time the ecosystem of technologies that supports online advertising has become so complicated and cumbersome that it actually makes it harder for advertisers to invest more money to market effectively, putting the industry’s growth at risk.