What advertisers need to know about Apple's intelligent tracking prevention

by Jerelle Gainey, 06 Oct 2017

What happened?

Today, the default setting of all Safari browsers is to block third-party cookies that are dropped by domains other than the domain of the URL to which the user browsed. However, when a user clicks on an ad, the cookie dropped is treated as a first-party cookie. This is because a click gets routed through the ad network domain and therefore is treated as a first-party cookie.

iOS 11 will change the concept of a first-party cookie. Intelligent Tracking Prevention (ITP) puts restrictions on whether advertisers can continue to read or update first-party cookies when the user is not directly on the business’s site. In other words, it affects whether a company can access first-party cookies in a third-party context. In the first 24 hours, the cookie acts exactly like it used to – and can be used for retargeting and conversion tracking. So, if you click on ad, you can be retargeted and your conversions tracked for exactly 24 hours. For the next 30 days, the cookie lets you login on-site, but cannot be used for retargeting or conversion tracking. After 30 days, the cookie is purged from the browser.


Why is Apple doing this?

A blog post by Apple WebKit security engineer John Wilander explains that ITP builds on Safari’s existing default blocking of third-party cookies and “reduces cross-site tracking by further limiting cookies and other website data.” ITP is aimed largely at limiting pervasive (according to Apple) retargeting practices rather than disrupting advertisers’ ability to track ad campaign performance.

Apple’s new technology tightens Safari’s restrictions on the management of third-party cookies. It does not block ads online but does prematurely delete third-party cookies for advertising retargeting and measurement, and so it obstructs conversion attribution, as well as the recording of user behavioral histories (i.e., it blocks the formation of cookie-based audiences).

How will this impact digital measurement?

This change impacts mobile Safari (some sources state over 50% market share) and desktop Safari (around 10% market share) in the U.S.

We’re currently monitoring the actual impact of this development very closely, but below are some common expectations by various advertising organizations:

  • This will affect most ad buying platforms
  • Retargeting ability will be limited to 24 hours post first-party interaction with the browser
  • The cost of impressions on Safari will drop, while the cost on other browsers will increase
  • There will be a net loss of conversions so CPAs could increase
  • Walled gardens will not be affected as they are dropping first-party cookies on users frequently
  • Organizations and tools that use cookie-less measurement will not be impacted as much, as they typically derive insights from other attributes and user behaviors
  • Solutions that use first- party cookies in first-party context, such as Google Analytics, will not be impacted
  • Platforms leveraging cross-device graphs will mitigate the impact of this development.
  • Google has implemented a solution to maintain measurement in Google Adwords by connecting Google Analytics to your Adwords account
  • Google will use modeling based on historical conversion activity to record conversions from Safari in AdWords if you do not connect your Google Analytics account to Adwords
  • DoubleClick Search will begin using statistical modeling to estimate website conversions that could not be measured from Safari, and include them in your DoubleClick Search reporting