WTF Happened to Mobile Advertising in 2021?

person using phone

By Roman Garbar, Marketing Director of Tenjin

For mobile marketers, 2021 has been a year of unprecedented flux prompted by Apple’s de-facto removal of IDFA and implementation of the App Tracking Transparency framework. We knew it was coming — iOS14 and the looming IDFA changes were announced as far back as 23 June 2020 — but most of us didn’t know what to do about it.

By the time the bulk of the changes were about to be made, in late April 2021, things had reached fever pitch and mobile advertisers and publishers felt like they were standing on the edge of an abyss.

Yet, fast forward another eight months and due to a narrative of continued mobile growth, dominated by already-gigantic publishers, you could be forgiven for thinking the struggle of post-IDFA marketing is yours and yours alone.

The truth is, as ever, not as clear-cut as this. Let’s take a look at WTF actually happened to mobile advertising in 2021, how we coped, and what the future holds.

The Rise of Android Stores and Alternative App Stores

iOS14.5 accelerated a mobile marketing shift that was already underway: the reallocation of budgets from iOS to Android platforms. In March-April 2021, iOS held 52% of ad spend share.

In April-May, there was a swing of four percentage points and Android received more than half (52%) of budgets for the first time. Between June 1 and July 1, advertising spend on iOS subsequently fell by about one-third.

It’s not as simple as budgets shifting from iOS to Google Play, either, although this is of course a major consideration.

Alongside it, we saw more marketers look to platforms such as Huawei AppGallery in China, where Google Play is unavailable and Apple device ownership is low. AppGallery and other players such as Samsung Galaxy Store are rapidly building out their ecosystems, creating a wider variety of campaign routes available to marketers.

The Era of Advanced Analysis on iOS  

The release of iOS15 in September expanded on some of iOS14.5’s key elements such as App Tracking Transparency (ATT), as well as introducing marketing tools such as new Product Pages to iOS after a five-month gap. Additionally, more publishers are defaulting to using Apple’s own advertising business, Apple Search Ads, although the numbers doing so are often overstated.

The biggest change is SKAdNetwork data, anonymized marketing data that comes directly from Apple, being freely available to marketers rather than just ad networks. The challenge is figuring out how best to generate insight from it and how it can be reconciled with data from other sources, including from users who have opted in to App Tracking.

Across the mobile marketing landscape, this remains a work in progress. While new tools and educational resources have been created, it’s safe to say making the most of SKAdNetwork has not been a frictionless experience for most marketers.

Temporary Solutions Persist

For this reason, some app publishers have chosen to operate in a state of limbo. With only around 25% of users opting in to App Tracking globally, tracking methods such as ‘Fingerprinting’ (often referred to as ‘Probabilistic Attribution’) endure. Fingerprinting collects software and hardware information about a user to attribute them to an ad campaign.

This is despite Apple coming out against Fingerprinting. It has reduced its effectiveness for users of Private Relay (iCloud+ service) by removing user IP addresses as a signal and creating Fingerprinting defences for its Safari browser on iOS.

Fingerprinting likewise only works for ad networks that use links in their ads, meaning it does not work for Facebook, Google, or Snapchat. How long these stopgap methods can go on remains to be seen, but their shelf life is certainly limited and marketers are delaying the inevitable pain of revamping their methods.

It’s Still All About David vs Goliath

There’s a reason it sometimes feels that you’re alone in struggling with privacy-first marketing. It’s because you mostly hear about how, despite the changes, major publishers are hitting new revenue records.

The reality is that this is made possible by already significant resources. Large publishers can mine insights from data in-house using large data science and R&D teams, or simply bring more user data into their ecosystem by acquiring smaller publishers. They have the freedom to experiment in their marketing, too, without fearing that they’ll be unable to pay the bills at the end of the month.

For the 99% of mobile publishers, many of whom are used to relying wholly on a Mobile Measurement Partner (MMP), this is of course not the reality. Nevertheless, some have started building their own Business Intelligence (BI) stacks that bring together diffuse datasets and store and analyze them using the tools they already have.

This enables indie and mid-size publishers to execute on their growth strategies and keep pace with the big players, even without sizable monetization teams or in-house data science.

Facebook Gives up on Attribution

When iOS15 was introduced, Facebook quickly decided to defer to SKAdNetwork for its attribution — the process of connecting a marketing action with an app install. But the big surprise came in October 2021 when it quietly began using Google Play Install Referrer to pass Android install attribution data. Like SKAdNetwork, this is available to all developers.

In all but name, this means Facebook has given up on attribution, deferring totally to Apple and Google frameworks. The impact on advertisers is as yet unclear, but we’re certainly looking at a more fragmented landscape that throws the role of MMPs into doubt. This possibly sets the stage for advertisers to become their own MMPs and take attribution in-house, or even for attribution to become effectively free.

2022 – Android Changes Expected

Though unexpected, Facebook’s decision to defer its Android attribution was a measured one. Mobile marketing’s direction of travel is set and it’s only a matter of time before Android follows Apple’s lead and implements its own set of privacy-first measures.

What this looks like is yet to be firmed up, but it’s coming, most likely in 2022. For mobile publishers still unclear how to rebuild their marketing stacks for SKAdNetwork, it’s going to sting.


With mobile advertisers still grappling with the post-IDFA world, more iOS developments expected and Android changes on the (near) horizon, 2022 will be turbulent too (not to mention the buildup to the deprecation of third-party cookies planned for 2023).

I expect to see the continued growth of global Android stores and firmer resistance to Fingerprinting that drives more publishers to take action and figure out how to use SKAdNetwork data, whether this is building their own BI stacks or using out-of-the-box tools.

If I’m certain on one thing, it’s that the vast majority of mobile marketers are in the same boat. For every Sony, Supercell or AT&T there are dozens more publishers that don’t yet have the answers for privacy-first mobile marketing. You’re certainly not alone in still figuring 2021 out!

About the Author

As Tenjin’s Marketing Director, Roman Garbar uses his extensive knowledge of mobile marketing analytics to educate indie and mid-size publishers on how to grow their apps and games.

About Tenjin

Tenjin is a mobile measurement platform that provides best-in-class tools and education resources for testing and scaling user acquisition. Headquartered in San Francisco, Tenjin was co-founded in 2014 by Christopher Farm and Amir Manji. Tenjin offers a single, comprehensive platform for mobile app analytics, attribution and ad network data aggregation, with a data warehousing solution for direct access to user-level data.