Unfortunately for Facebook, it would appear that there aren't very many people that are willing to have their app activity tracked.

How Many iPhone Users Opt Into User Tracking?

Analytics firm Flurry has released data on Apple's new App Tracking Transparency feature, which suggests that most iPhone users have chosen not to opt into app tracking.

The report claims that only four percent of iPhone users in the US, based on a sample of 2.5 million daily active users (DAU), have chosen to opt into app tracking. When looking at users worldwide, that statistic grows to 12 percent in a sample size of 5.3 million DAU.

It's worth noting that this is an ongoing analysis—these numbers are subject to change. Flurry says its report will be updated every weekday at 10am PST.

"This change [every app having to ask for permission to track] is expected to create challenges for personalized advertising and attribution, impacting the $189 billion mobile advertising industry worldwide," Flurry writes.

What Is App Tracking Transparency?

Following the release of iOS 14.5 for iPhone users, apps now have to ask you for permission to track you across other apps and websites. Every time you open an app for the first time, a prompt will ask you for permission.

Whatever you choose, you can always adjust every app individually in your iPhone's Settings, under Privacy and then Tracking. There's also a global switch to allow or disallow all tracking by default.

What Is Flurry?

Owned by Verizon Media (yes, the company that's selling Yahoo and AOL for $5 billion), Flurry Analytics brings aggregated insights to two billion mobile devices every month through over one million mobile apps.

Flurry says that its data helps acquire, retain, and monetize audiences:

This data translates to accelerated revenue and growth for app developers, an improved mobile experience for consumers, and best-in-class advertising opportunities for advertisers and brands looking to reach engaged mobile audiences.

What This Opt-In Rate Could Mean

You might not care about how many people choose to opt into user app tracking, but Facebook sure does.

To open up May 2021, Facebook launched a notice to try to convince users to turn on app tracking in the Facebook and Instagram iOS apps. Apparently, by turning on app tracking, you help keep them "free of charge."

We'll have to wait and see whether the world's most popular social media apps will start making you pay to view and publish posts. Seeing how a majority of users have turned user tracking off, it's clear that privacy is fair more important to people.