The advertising industry is continuously evolving.

From billboards to newspapers, from radios to television, and from desktops to Smartphones, technology has been changing the way that companies appeal to prospective consumers for decades. And efficiency has always been at the very heart of advertising. Businesses are looking to grow their top line at the most optimal return on investment possible.

The internet introduced new ways for companies to maximize that ROI of their ad spend. Search engines like Google (Nasdaq: GOOGL) and social networks like Facebook (Nasdaq: FB) have become massive platforms with billions of users. Together, they accounted for nearly 70% of the $370 billion the world spent on digital advertising last year.

But these walled gardens have their limitations, and there's a fast-growing ad tech industry that is leveraging technology to provide new ways to connect advertisers with content publishers. It's growing quickly, yet it is still highly fragmented and is undergoing a wave of consolidation.

How should growth-style investors, intrigued by the rapid pace of innovation in this gargantuan market, get exposure to the changes taking shape in this digital advertising space?

To help us answer that question, 7investing founder and CEO Simon Erickson recently spoke with PubMatic co-founder and CEO Rajeev Goel. PubMatic is a publicly-traded company based in San Francisco, whose mission is to fuel the potential of internet content creators. It trades with the ticker "PUBM."

In this exclusive interview with 7investing, Rajeev describes two of the most important innovations that have taken place in digital advertising during the past 15 years. The first was real-time bidding, which transformed the ad industry's transactions from static interactions to instantaneous online auctions. The second was a transition from desktop to mobile, which brought ads into apps and required them to be placed in different ways.

But importantly, Rajeev also believes there is a third important innovation taking shape in the digital ad industry today: the intense focus on consumer privacy. Several companies are transitioning away from third-party cookies, and consumers are demanding for prompts to opt-in before their data is tracked or shared.

Rajeev believes this trend could unlock a new wave of opportunities. Content publishers are increasingly looking to programmatic as a convenient and highly profitable way to generate revenue. As one of the clear innovators in the ad tech space, PubMatic is developing creative strategies to gain market share and to differentiate itself from competitors.

This interview is a must-watch for any forward-thinking investors interested in the future of advertising!

Publicly-traded companies mentioned in this interview include Adobe (Nasdaq: ADBE), Alphabet (Nasdaq: GOOGL), Apple (Nasdaq: AAPL), eBay (Nasdaq: EBAY), IPG (NYSE: IPG), NewsCorp (Nasdaq: NWS), Proctor and Gamble, PubMatic, The Trade Desk (Nasdaq: TTD), Zynga. 7investing's advisors or its guests may have positions in the companies mentioned.