What Is Apple’s Private Click Measurement?

1. Primary Objective of Private Click Measurement
2. Origins and Evolution of PCM
3. The Mechanism of PCM
   1. Click Side
   2. Triggering Event
   3. Attribution Report
4. Limitations of PCM
5. Future Enhancements
6. Conclusion

Primary Objective of Private Click Measurement

Apple’s PCM is primarily aimed at facilitating the measurement of ad clicks while ensuring a high level of privacy protection for users. The conventional method of web advertising attribution involves the use of cookies that carry user or device IDs, leading to cross-site tracking. This practice is detrimental to user privacy, and Apple’s PCM seeks to prevent it.

PCM measures direct conversions, enabling advertisers to determine the effectiveness of their campaigns by measuring which advertisements lead to sales or other desired outcomes.

Origins and Evolution of PCM

Apple first proposed PCM as a privacy-preserving measurement of ad clicks in May 2019. The proposal went through numerous revisions and discussions in the W3C Privacy Community Group, culminating in its current form. It’s now available in Apple’s Safari browser and from iOS 14.5 in iOS and iPadOS applications.

The goal is to standardize PCM for use in other browsers. To do this, a second independent implementation, such as Firefox, Brave, Chrome, or Edge, must exist.

The Mechanism of PCM

PCM operates by recording when clicks and conversions occur. When a click is followed by a conversion, the browser creates a report. PCM ensures privacy by strictly limiting the information included in the report and submitting reports to websites via an anonymization service after a delay.

Click Side

On the click source side, an 8-bit identifier is used. This allows 256 parallel ad campaigns to be measured per website or application. The click destination website, which seeks to attribute incoming navigations to clicks, is also recorded.

Triggering Event

To trigger click attribution, the destination website must send an HTTP GET request to the website where the click-through ads are running. This method is designed to support existing “tracking pixels” and facilitate easy adoption.

Attribution Report

The attribution reports are sent as HTTP POST requests. The report includes the source_engagement_type, source_site, source_id, attributed_on_site, trigger_data, and the version of the attribution feature.

Limitations of PCM

PCM, while providing privacy-friendly tracking, comes with certain limitations:

• PCM doesn’t support user mapping or capturing demographic user features.
• The time of the conversion, not the click, is recorded.
• Attribution reports are transmitted with a delay, randomly between 24 and 48 hours after the event.
• The attribution window is limited to 7 days. If the conversion happens later than 7 days after the ad click, it isn’t tracked.
• PCM doesn’t consider view-through ad attribution, i.e., attributing conversions when someone only sees an ad but doesn’t click on it.

Future Enhancements

The evolution of web standards necessitates continuous improvements to PCM. Among the changes expected are fraud prevention with unlinkable tokens, a modern JavaScript API for triggering events instead of legacy tracking pixels, and allowing attribution reports to be sent to advertisers as well.

However, misuse of PCM for tracking purposes or using it in conjunction with unrelated means of tracking users, events, or devices may lead to blocking from using PCM and potential future measurement features.

Conclusion

While PCM represents a significant stride towards privacy-preserving ad tracking, it also underscores the need for continued innovation and improvements in the realm of digital advertising. As the digital landscape continues to evolve, so should the measures to protect user privacy and provide valuable insights to advertisers.

With its pioneering approach, PCM serves as a testament to Apple’s commitment to safeguarding user privacy while still catering to the necessities of the digital advertising ecosystem. As PCM continues to evolve and adapt to the changing digital landscape, it promises to foster a more privacy-centric advertising environment.