Ad blockers have been around for some time now, but they reached an unprecedented level of attention this year when Apple rolled out its iOS 9 update in September, enabling ad blocking on mobile devices via its default Safari browser.

Apple’s release catapulted advertisers’ concerns around ad blocking to new heights, with many CMOs and top-level marketing executives just recently entering the conversation and discovering what’s at stake.

For the marketing and brand leaders not involved in their brand’s day-to-day display ad strategy, we turned to digital marketing expert and regular Marketing Land contributor Rob Rasko for a high-level overview of the ad blocking landscape.

Consider this the “crib notes” on ad blocking — a cheat sheet for CMOs to better understand what ad blockers are, the content they block, and how they may impact a brand’s overall advertising strategy.

What CMOs Should Know About Ad Blockers

Rob Rasko, 614 Group Founder 

Amy Gesenhues: Let’s start with the basics. Can you give us a high-level overview of what ad blockers are and how they work?

Rob Rasko: Ad blockers are, quite simply, browser plug-ins or apps that block digital ads from displaying on your screen.

They can work in a number of technical ways, but from a high level, they all read the code of a web page and intercept the call to display an ad. They see what your browser is loading, recognize certain qualities of an ad, and then prevent it from rendering.

More technically, they can either block an entire domain that serves ads or they can recognize the scripts that call the ads and prevent them from executing.

Amy Gesenhues: Why all the recent hype around ad blockers, and why should CMOs be concerned?

Rob Rasko: A lot of the discussion around the why of ad blocking centers around consumer frustration with the quantity and the quality of ads — certainly CMOs should be listening to the conversation.

If there is a continued push to “better advertising,” that’s something I would be listening for.

Also if ads are getting blocked that means there are less ads in the market from a supply perspective, which could lead to a scarcity problem in digital – words which have not been said sequentially in a meaningful way before.

Amy Gesenhues: Do you have any data on the number of consumers currently using ad blockers?

Rob Rasko: Ad blocking has reportedly grown in the past year, particularly as more folks seem to be talking about the problem.

According to a recent study published by an industry trade, 200 million people are using ad blockers worldwide, with about 45 million people using them in the US, but I am not yet ready to take these numbers as gospel.

These companies have an incentive in scaring the market, and so I think we need to proceed rigorously in finding out the true scope of the issue.

Amy Gesenhues: Who are the major players in the ad blocking landscape?

Rob Rasko: There are major players on both sides. There are a large number of ad blocking plugins for browsers, and then there are the newer players, tackling the more complex problem of blocking ads in mobile apps.

Adblocker is the most popular ad blocking application, and apps such as Crystal, Blockr and Peace have all seen spikes in popularity. Fighting the blockers are PageFair and Sourcepoint.

Additionally, trade bodies like the IAB are doing their part globally to help educate the market on what ad blocking means and how this choice is affecting the consumer.

Amy Gesenhues: What types of ads are most likely to be impacted by ad blockers?

Rob Rasko: All ads — from display, to video, to mobile — can be blocked, although in our opinion, in-app ads will be blocked less of the time due to the the technical nature of blocking that way.

Amy Gesenhues: How are ad blockers likely to impact a brand’s ads or search marketing efforts?

Rob Rasko: A brand might focus their efforts on native advertising or content marketing, which is delivered differently than traditional advertising. So far, native advertising isn’t impacted by ad blockers.

However, there are questions about whether or not native advertising can reach the scope and scale of display advertising. In-stream video advertising is also faring better than display advertising in the fight against ad-blocking, so we could see more budgets shift from display to video advertising as well.

Amy Gesenhues: What questions should CMOs be asking their teams or agencies about ad blockers?

Rob Rasko: It’s early days — there are new analytics coming online from the companies like Sourcepoint and Pagefair which are releasing data regularly.

I would suggest keeping an eye on the developments at the moment and not overreacting if there is a change. The actual scope of the problem is smaller than people are saying in the media — that’s what I am hearing privately.

Amy Gesenhues: How do you see ad blockers impacting the industry going forward?

Rob Rasko: It’s certainly a scary thought that many ads would be blocked, however, the balance between free content and subscription only content hangs in the balance.

If everyone blocked all the ads and content producers went 100 percent paywall or subscription, I don’t think consumers would be that thrilled either.

Amy Gesenhues: What’s your top advice for CMOs?

Rob Rasko: Focus on the big picture. Make sure you know the partners you are working with, remember content and context matter and so does user experience.

If you can connect all three, I believe this issue will be a smaller challenge than some others we are facing like fighting ad fraud or converting to a viewable currency.

Find Marketing Land’s full coverage on ad blocking here: Display Advertising — Ad Blocking.