Missing Document Referrer in Pinterest Referrals

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Currently, referrals to non-SSL websites from the Pinterest mobile app are showing as "Direct" in Google Analytics—this means your Google Analytics reports for "Social" attribution are taking a nose dive. Your social marketing and content teams will not like this one bit!

Missing Document Referrer Causes "Direct" Traffic

We started noticing around mid-March that  Pinterest referrals were dipping. Meanwhile, direct visits were increasing. The referral decline was about the same rate as the increase in direct traffic: [caption id="attachment_31632" align="alignnone" width="730"] Pinterest referrals replaced by Direct traffic - Missing HTTP Referrer Issue Beginning on 3/14/2016, Pinterest mobile referrals (blue) were on the decline and replaced by Direct traffic (orange).[/caption] Applications like Facebook, Twitter, and Pinterest use an embedded web browser. This allows users to interact with their content feeds without leaving the application. [caption id="attachment_31658" align="alignright" width="300"] Facebook Webview Browser Facebook wraps the visitor experience in a webview browser.[/caption] These embedded webview browsers are typically custom built. Developers seem to forget to include support for important things like document referrer. Whoops!
Any session that does not include the document referrer is bad news for attribution.  Google Analytics has no way to attribute inbound traffic to the appropriate source without the document referrer.
This issue effects GA attribution on non-SSL websites for referral traffic coming from the Pinterest mobile app.

Test App Referrals Using a Network Proxy Tool

[caption id="attachment_31648" align="alignleft" width="300"] Missing Document Referrer Issue - Charles Web Proxy Using Charles Web Proxy, we can inspect network calls coming from the Pinterest App.[/caption] Using Charles Web Proxy, we can inspect Google Analytics pixels while browsing any mobile app. This is a wonderful tool to add to your Digital Analyst bag-o-tricks. We are looking for the existence of " &dr=" in the URL of the GA pixel.  Note, "&dr=" is the Google Analytics Measurement Protocol field for "document referrer". Use an "include" filter to keep out the additional network noise. This is how to setup the filter to include only Google Analytics pixels: Proxy > Recording Settings > Include > Add: *.google-anlaytics.com/collect The test steps to reproduce this issue are as follows:
  1. User clicks on link in Pinterest (iOS or Android)
  2. Pinterest loads page in embedded webview browser
Success Condition:  The test passes if Google Analytics appends " &dr=pinterest.com" to the page view. This is a " Social" visit. Fail Condition: Without the "&dr=" parameter, GA will not append a source or medium. This is a " Direct" visit.

Examining the Results

First, we will demonstrate a successful test. Facebook has a similar embedded browser experience so we will test their app first: [caption id="attachment_31657" align="alignright" width="300"] Document Referrer Test - Facebook The Facebook embedded browser has the correct &dr= variable. Test Passes![/caption]
  1. User clicks on link in Facebook app
  2. Facebook loads page in embedded webview browser
  3. Result: "&dr=" parameter exists! This means our test passed for Facebook
Now perform the same test using the Pinterest mobile app: [caption id="attachment_31659" align="alignright" width="300"] Document Referrer Test - Pinterest The Pinterest embedded browser does not have the &dr= variable. Test Fails![/caption]
  1. User clicks on link in Pinterest app
  2. Pinterest loads page in embedded webview browser
  3. Result: "&dr=" is not present! This means our test failed for Pinterest
NOTE: This issue only occurs for non-SSL webpages. If we were to use a URL like  " https://www.website.com/" then Pinterest would pass the test.


Perhaps Pinterest is telling the world it is time for all sites to upgrade to SSL encryption! That is not the worst idea in the world, but I do believe this is an oversight on their part. After all, Pinterest has a shared fate with publishers and being able to attribute value is a crucial part of that relationship. In the mean time, we are left with two ways for this problem to be resolved:
  1. Turn on site wide SSL encryption and fist bump your Infra-Ops Team. (Seriously, why not do this?)  OR
  2. Patiently wait for Pinterest to include document referrer support for both HTTP and HTTPS endpoints in their embedded mobile browser
Not the best solutions, but knowledge is power... right? Hopefully, this helps to explain why you might be experiencing a drop in Pinterest referrals. If you have any questions let us know in the comments. If you have seen this issue in other platforms then we would love to hear from you as well!