Dustin Cha

Co-founder and Co-CEO of Ad-Shield — measuring and monetizing dark traffic for publishers.

[Dustin Cha @DustinCha_]

Hats off to Confiant in their role exposing this huge cybersecurity threat.

It's incidents like this that are the major cause of adblocking growth in the West.

IT teams are shutting out ads across networks, devices, and wifi.

[Mike Butcher, Editor, Pathfounders.com @mikebutcher]

Fucking hell. Good reason to install an ad blocker, but that will collapse media ad revenues. Great work guys... https://t.co/OiRXcuJg6I

[Dustin Cha @DustinCha_]

@adamheimlich

[Dustin Cha @DustinCha_]

Just sayin'

[Dustin Cha @DustinCha_]

@adamheimlich lol of course: https://t.co/CfEMZikcDC

[Dustin Cha @DustinCha_]

@adamheimlich https://t.co/dU5wn8YGNt

[Dustin Cha @DustinCha_]

Yo! There's 3 limitations with this:

1. It's from eyeo. The grounding of their reports comes from the adblockers they make (e.g. Adblock Plus). Which, today makes up around 20% of total adblocking traffic (used to be 80-85%). A lot gets missed, since many adblockers today block analytics tools - including many made specifically to measure adblocking traffic.

2. It masks a demographic shift. 10 years ago the big incline you see there was caused by mobile adblocking in Asia. A big chunk of that dropped off, but it got replaced with a rise of adblocking in the West (particularly the US).

3. It's from 2023. In the past few years alternative implementations of adblocking have taken off - through VPNs, apps, home routers, public wifi, IT-level adblocking installed in companies, government departments, and educational institutions etc (that's a big one).

[Dustin Cha @DustinCha_]

@BradAT 100%. And its wild you have to make this argument...

[Dustin Cha @DustinCha_]

@JohnathanBarnes That's literally what is happening!

LLM bots accessing websites block the ads and consume the content.

It's not "adblocking" it's "agentic"

[Dustin Cha @DustinCha_]

Sensing a theme... 🤔

[Dustin Cha @DustinCha_]

At this point it’s still not eniterly clear why only 5 ID/tracking vendors ended up on the iOS 27 hardcoded blocklist. As opposed to a more comprehensive list.

My guess is a test, before ramping up with the larger dynamic list.

[Dustin Cha @DustinCha_]

Have been talking with publishers about this the past few days. The general sentiment so far is:

• Not seeing a huge impact, small %
• Assessing how the situation develops before reacting

[Dustin Cha @DustinCha_]

@aripap @This_Liss Was just about type the same. 7 mins too late!

[Dustin Cha @DustinCha_]

@mjbarash That is a more powerful contrast, for sure

But from Apple's perspective I'd suggest they aren't "coming after" anyone

The whale doesn't chase the wake; the wake happens because the whale moves. So to speak.

[Dustin Cha @DustinCha_]

Worth keeping in mind alongside Apple's recent blocks on TTD and post-cookie ID providers:

In July 2026, Apple changed its ad terms.

Apple Ads used to run on "Apple software applications or Apple devices."

Now the terms cover "devices, operating systems, software or web applications, or other platforms or properties."

That suggests room to expand, which could include in-app, Safari, and beyond.

As the utility of independent adtech goes down, the relative value of Apple Ads goes up.

[Dustin Cha @DustinCha_]

Apple has unblocked The Trade Desk on iOS. Well, sort of...

Quick recap. Since iOS 27 launched mid-September, Safari and every browser on iPhone has been blocking a short, unpublished list of adtech domains, even in normal browsing mode.

Eight domains were hardcoded onto a blocklist in WebKit:

→ The Trade Desk (adsrvr .org)
→ The Trade Desk's Unified ID 2.0 (uidapi .com)
→ ID5 (id5-sync .com, eu-1-id5-sync .com)
→ LiveRamp (rlcdn .com, pippio .com)
→ Permutive (permutive .com)
→ Audigent (ad .gt)

All but one are exclusively identity and tracking domains. The odd one out is adsrvr .org, which TTD also uses to actually serve ads. So TTD's ads went dark on Safari.

Yesterday, Apple released a new iOS 27.2 beta build. In it, adsrvr .org is off the blocklist, clearing the way for TTD to serve ads again.

So why "sort of"?

1️⃣ UID2 stays blocked. uidapi .com is still on the list. TTD's ad serving domain is off, but its identity solution isn't. Even once TTD's ads can load again, it will be bidding on Safari with less to go on.

2️⃣ The ad serving block stays in place until iOS 27.2 ships. We still have iOS 27.1 coming first, around October 20, without the fix. iOS 27.2 probably won't ship until we're deep into Q4, during what is peak ads season.

Meanwhile, the bigger change is still on its way.

On September 25, Apple added new code to WebKit. Once it ships, Apple can add domains to the blocklist remotely, whenever it chooses, without anyone needing to update their iPhone. That code isn't in yesterday's iOS 27.2 beta, so for now the list stays hardcoded. But 27.2 is the earliest realistic window for it to arrive.

Why does that matter?

Last week, AdExchanger reported that Apple has a much longer blocklist ready to go: hundreds of adtech, martech, data and identity companies. Those companies may not even know they're on it.

Apple hasn't confirmed any of this. But if it goes ahead, remote updates are most likely how that list gets switched on. And if they arrive with 27.2, Apple could start growing the list right in the middle of peak holiday season.

The same update that takes TTD off the list could be the one that gives Apple the capability to block far more.

[Dustin Cha @DustinCha_]

@EricTilbury_RTB Also worth noting they seem to be happy to bias toward blocking, to serve their privacy agenda.

Even if that means there may be second-order effects like this recent incident with adsrvr .org — short-term or long-term.

[Dustin Cha @DustinCha_]

@EricTilbury_RTB Yes on both points:
• Collateral damage
• Apple is going hard after anything with a whiff of tracking/IDs

Keep in mind that TTD will continue to be blocked until iOS 27.2 releases (this is where adsrvr .org is set to be unblocked). That will probably be around halfway into Q4.

[Dustin Cha @DustinCha_]

@garethglaserjr Its been unblocked in the latest iOS build, which will ship in iOS 27.2, likely mid November-ish

[Dustin Cha @DustinCha_]

Live from TTD HQ

[Dustin Cha @DustinCha_]

Assuming this fixes TTD's ability to serve ads, the bummer here is iOS 27.2 probably won't ship until deep into Q4, during what is peak ads season.

iOS 27.1 will come first, around 20th Oct.

[James @JamesHercher]

movement!