Welcome to the final quarter. We now move into analytics and advanced strategy. And we start with one of the most disruptive events in email analytics history: Apple Mail Privacy Protection.
This Week’s Lesson
In September 2021, Apple rolled out Mail Privacy Protection (MPP) in iOS 15 and macOS Monterey. When enabled, Apple pre-fetches email content through their servers — including tracking pixels — before the user even opens the email. This means every Apple Mail user appears to have opened your email, whether they did or not.
Impact: Apple Mail's share of email clients is roughly 50-60% depending on your list. If half your subscribers are Apple Mail users, roughly half of your 'opens' are now phantom opens triggered by Apple's servers — not human eyeballs.
What this means for open rate as a metric: it's no longer trustworthy as a measure of human engagement. Open rates inflated by MPP can look like improvement when engagement is actually flat or declining.
What to measure instead: Click rate (clicks require a human action — not affected by MPP). Reply rate (same). Website visits from email links (measurable via UTM parameters). Unsubscribe rate (a real signal of disengagement). Revenue attributed to email. Spam complaint rate.
List segmentation impact: if you were segmenting on 'opened in last 90 days,' that segment is now artificially large due to phantom opens. Switch to click-based engagement segmentation: 'clicked in last 90 days' is a genuine engagement signal.
Deliverability signals: inbox providers like Google still measure real engagement (they see whether the email is read, moved, replied to) — not just pixel fires. Your delivered-to-inbox rate and domain reputation in Google Postmaster Tools remain valid indicators.