With Apple’s introduction of Mail Privacy Protection, three major providers in the email ecosystem (Apple, Google, Yahoo!) now use proxy servers at the mailbox provider or app level to cache email images—including tracking pixels. Image caching can affect open, geolocation, and device data.
While proxy data is still a valuable signal, it can be best understood separately from other kinds of open signals. Platform Distribution gives you the context to see which opens represent proxy engagement and which represent user engagement.
The Platform Distribution widget segments Everest engagement data into provider categories so it is clear which pixels are fired from proxy services and which pixels are fired from real user opens. These categories include Apple Privacy Proxy, Google Proxy, Yahoo Proxy, Desktop, Mobile/Tablet, and other.
Desktop and Mobile
For most mailbox providers, provider category will fall into either Desktop or Mobile/Tablet, determined by device. (We’ll address Apple devices in a moment.) These categories reflect real user opens and give you the maximum information about engagement behavior.
- Desktop includes both static desktops and laptops.
- Mobile/Tablet includes phones and tablets.
- Webmail can fall into either category.
For example, accessing the Outlook desktop app on a laptop would count as Desktop. So would accessing Outlook.com webmail in a Chrome browser on the same laptop.
Google Proxy and Yahoo Proxy
Google and Yahoo! (including Gmail, AOL, and related services) get their own provider categories, called Google Proxy and Yahoo Proxy.
Both Google and Yahoo! download email images for security purposes before the recipient sees them, then use a proxy server to rehost those cached images. This means that the only time the Everest tracking pixel will fire for Google and Yahoo! is when those mailbox providers cache the images. Because caching happens at open, Google Proxy and Yahoo Proxy are still good indicators of recipient open times.
The Gmail and Yahoo! mobile apps will always trigger a provider category of Google Proxy or Yahoo Proxy. In most cases for these providers, using a desktop app or accessing webmail via browser will also trigger one of those provider categories, overriding Desktop or Mobile.
Apple Privacy Proxy
With the introduction of Mail Privacy Protection comes the Apple Privacy Proxy category. Since Apple is not only a device manufacturer but also a software developer (the Mail app), Mail Privacy Protection has additional reach.
The Mail app is the default client on all Apple devices (iPhones, iPads, and Macs). With Mail Privacy Protection, Mail goes a step further than Yahoo! and Google: it can fetch emails in the background when plugged in with wifi enabled. Mail then caches images at the time of fetch, firing the pixel long before the recipient opens the message.
Because Mail can be used with any mailbox provider, its impact extends beyond iCloud addresses. For example, if you use the Apple Mail client to read emails sent to your Gmail address, any pixel-based tracking generated by those interactions will be impacted by Mail Privacy Protection.
Other
This provider category includes smart TVs, gaming consoles, and other anomalous results that don’t fit neatly into other categories. If a user installed a non-Apple OS on an iPhone, for example, that could prompt a category of Other.
The chart below provides just a few examples of how provider category is assigned.
Domain |
Device |
Client |
Provider Category |
@gmail.com |
iPhone |
Gmail app |
Google Proxy |
@yahoo.com |
iPhone |
Mail app |
Apple Privacy Proxy |
@yahoo.com |
iPhone |
Yahoo! app |
Yahoo Proxy |
@mydomain.com |
Windows laptop |
Outlook desktop app |
Desktop |
@comcast.com |
Android |
Webmail in browser |
Mobile |