How Do Mobile Ad Blockers Work? A 2020 Guide

Chris Shuptrine
cardimage

As you look to monetize your app or mobile site with ads, it’s important to understand what mobile ad blockers are and how they could impact your revenue.

The below article touches upon how mobile ad blockers work and offers strategies for monetizing mobile adblock users.

I’ll be focusing here on mobile ad blocking, but you can read about desktop ad blocking here.

First off, why should I care about ad blockers?

Ad monetization relies on ads being shown and tracked (and ideally seen and interacted with). Ad blockers prevent these ads from appearing (and tracking tools from working), preventing you from monetizing those mobile users during those sessions.

mobile ad blocking example
mobile ad blocking example

(The banner ad at top is blocked, leaving an empty space)

According to Blockthrough, mobile ad block usage rates are high - at 527 million, well above desktop's 236 million.

How much do mobile ad blockers decrease my revenue?

That will depend on a few factors:

  • Percentage of mobile vs desktop traffic

    If your company makes mobile app games, you'll obviously be more affected than a desktop-focused site. If you do fall under the latter, we recommend reading our desktop ad blocking article.

    Regardless, data from the past few years has shown that roughly 60% of all web traffic comes from mobile (this excludes in-app activity) - so, no matter what, your mobile web traffic is likely not insignificant.
    mobile app vs mobile site
    mobile app vs mobile site
  • Percentage of in-app vs mobile web traffic

    Keep in mind that "mobile" comprises both iOS/Android/etc apps AND browser-accessed mobile websites. The two operate quite differently, with in-app ads more difficult to block.

    As you can see below, US adults spend about 85% of their mobile time in apps and just 15% using a mobile browser.
    mobile web vs mobile apps
    mobile web vs mobile apps
  • Your users' mobile browser preferences

    While most mobile browsers contain ad blocking either by default or opt-in, the #1 player - Chrome - does not. As such, the revenue impact of blockers will depend on how many of your users browse with Chrome.

    mobile browser ad block
    mobile browser ad block
    On tablets, Chrome is at 46%, versus Safari at 44% and others adding up to about 10%.
  • What type of ads you're showing

    While mobile ad blockers stop third-party and programmatic ads, they do not appear to impact server-side native ad products, like Pinterest's Promoted Pins or eBay's Sponsored Listings.
    ebay ads
    ebay ads

How does mobile ad blocking work?

Below outlines the different types of ad blocking tech.

One big difference between mobile and desktop ad blocking is that the latter relies on browser extensions - which are not applicable on mobile. Google Chrome, for instance, offers extensions on its desktop browser, but you can't download those same extensions for their phone or tablet browsers.

Content Blockers (Safari Browser)

Apple's Safari captures 20-30% of the mobile browser market share and 44% of tablets. Apple allows users to download content blocker apps from the App Store, such as eyeo's Adblock Plus (which is the most-common desktop ad blocker).

Upon downloading, users then have to go to their Safari settings and enable the ad blocker to work.

safari mobile ad blocker
safari mobile ad blocker

These content blocking apps work by listening to outgoing HTTPS requests upon page load and matching those to a list of known third-party ad tech vendors.

Before Safari then renders the page, these apps tell the browser what requests should be blocked.

To identify what to block, most of these apps pull from the same regex list, called EasyList, which contains thousands of expressions like:

easylist ad block
easylist ad block

EasyList is maintained through a user community that identifies unblocked content, which is reviewed and potentially added to the list.

These apps do not appear to block custom native ad units, such as Twitter's Promoted Trends, Google's Search Results Ads, and so on. This is compared to desktop ad blockers, which are able to block such native ads, as they do both HTTPS request blocking and hiding of specific CSS elements.

Mobile browsers with built-in ad blocking (Firefox, Opera, etc)

Most mobile browsers beyond Chrome do offer some sort of built-in ad blocker, whether that's by default, such as UC Browser and Brave, or by opt-in, like Firefox and Microsoft Edge. These account for approximately 10%-20% of total mobile web traffic.

These browsers exist as apps that you can download from the Google Play Store, iOS App Store, and so on.

In Blockthrough's aforementioned report, for example, mobile ad block usage increased from 167M to 527M in five years - but the bulk of it is from UC Browser, which has 405M users and a built-in ad blocker.

blockthrough ad blockers
blockthrough ad blockers

For browsers where ad blocking isn't enabled by default, like for Firefox, opting-in is easy (granted, FireFox does have Firefox Focus, a separate browser with ad-blocking on by default):

firefox ad block
firefox ad block

These built-in ad blockers appear to all use the HTTPS method that Safari content blockers do - which means they'll stop ads from third-party ad vendors, but will still show custom, native ad units.

In terms of what block list the browsers are using, it's a mixed bag. Opera, for instance, uses EasyList by default, while Brave is a proprietary list.

VPNs/DNS

VPN (virtual private network) ad blockers work through VPN clients. They block ads by stopping or redirecting DNS (domain name system) requests to ad network servers. DNS ad blockers do the same, but require users to install them as their DNS server.

Like browser-based ad blockers, VPN ad blockers work by listening to and blocking any HTTPS requests from known ad vendors.

The benefit of VPN/DNS ad blockers is that they can block mobile web and in-app ads.

These solutions approach blocking ads from a couple of ways.

Connectify, for example, turns your computer into a hotspot that you can connect your mobile devices to and toggle off ads.

NordVPN is a VPN app that you download and have on in the background. Its "CyberSec" option lets you block ads and malware.

nordvpn ad block
nordvpn ad block

AdAway is a popular Android VPN tool that was removed from the Google Play Store, but can be downloaded by rooted phones and uses the hosts file.

Here’s a quick summary of the different types of mobile ad blocking tech:
Type Block Mobile Web Programmatic Ads Block In-App Programmatic Ads Block In-House Native Ads
Content Blocker Apps (Safari) Yes, Safari-only No No
Browsers with build-in blockers Yes, for that respective browser No No
VPN/DNS solutions Yes, across all browsers, including Chrome Yes No

How to monetize your ad block users

The options for monetizing your mobile ad block users are limited (we have an extensive list of ideas for desktop ad block monetization here, though).

It's partly because many desktop approaches involve identifing, in real-time, who is using an ad blocker, then prompting them to turn it off or displaying different content.

gated ad blocker prompt
gated ad blocker prompt

In testing, while many desktop sites prompted me to turn off my ad blocker (Forbes, The Onion, etc), not a single one did on mobile - indicating such tech doesn't port over to mobile well.

That said, there is good news for companies worried about mobile ad blockers:

  1. There's no data to suggest that VPN/DNS ad blockers have much market penetration. This means your in-app ads should be relatively unaffected by mobile ad blockers.

  2. Additionally, Chrome's mobile browser doesn't allow for ad block extensions (which it does on desktop). As Chrome's mobile usage share is 50%-60% - that means (barring high VPN usage rates) that you can still monetize most of your mobile web traffic. Plus, Safari accounts for another 20%, and installing a content blocker involves many steps, making it unlikely many Safari browsers use an ad blocker.

  3. Mobile ad blockers do not appear to hide CSS elements (and instead only block HTTPS requests), which means that in-house native ads aren't getting blocked on mobile, even though they can on desktop.

Still, below outlines some ideas you can take to minimize the impact of mobile ad blocking:

Join the Acceptable Ads program (AA)

The Acceptable Ads program is a non-profit founded by eyeo, the creator of AdBlock Plus.

It’s a way for publishers to pay to have their ads whitelisted by certain ad blockers. Anyone with fewer than 10 million affected monthly impressions can join this program for free (assuming their ads are deemed acceptable), but for larger sites they charge a 30% cut of all incremental revenue gained from being whitelisted.

The upside of joining AA is being able to monetize users who have downloaded AdBlock Plus from the App Store or an AdBlock Plus app from the Google Play Store (or a similar ad blocker who is also in the program).

But joining won't help you monetize anyone using an alternate solution, like a VPN or a third-party browser, so you'll likely unlock little new mobile traffic.

Prompt users to download the app instead

If your ad revenue is higher in your apps versus your mobile site (potentially caused by ad blockers), then you could prompt anyone on a mobile device or tablet to open the page in the app instead. This is the approach Reddit takes, as their mobile site repeatedly pushes people to read the thread in the app, not the browser.

reddit ad blocker
reddit ad blocker

Build an in-house ad platform

Mobile ad blockers block pre-identified HTTPS requests that correspond with a known ad vendor. If you were to build your own ad product - like LinkedIn, Amazon, and many others have - you would not have to worry about your ads being caught by mobile ad blockers.

amazon sponsored products
amazon sponsored products

As such, this path would be advised if you're finding mobile ad blocking is having a sizable impact on your revenue.

You can build such a platform yourself or use ad serving APIs to cut down the work from years to weeks.

Summary

The biggest takeaway here is that ad blocking on mobile is fragmented - by device, operating system, site versus apps, etc - and is much harder to address than it is on desktop, where 90%+ of ad blocking happens via browser extensions.

On the flip side, if most of your mobile revenue is coming from in-app ads - or you have built your own ad server - then mobile ad blocking is unlikely to cause much pain.

Have any thoughts or comments on mobile ad blocking? We'd love for you to join the discussion below.

Join the Ad.Product community

Sign up for our monthly newsletter and to be notified of member-exclusive events and opportunities.

Ad.Product is the first community for product managers, engineers, and others to discover and discuss how to build innovative, user-first ad platforms.

Chris Shuptrine

Recommended Articles