What is a “foldering” report?
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You've probably run an inbox placement test and seen a breakdown showing how many messages landed in Primary, Promotions, Social, or Spam. That breakdown is called a foldering report.
A foldering report tells you which folder or tab each test message landed in, broken down by mailbox provider. So instead of just knowing "70% inboxed," you know that at Gmail your messages are splitting 40% Primary and 30% Promotions, while at Outlook they're all going straight to Focused. That's a meaningfully different picture.
This matters because "inbox" isn't one thing. Gmail alone has Primary, Promotions, Social, Updates, and Forums tabs. Yahoo Mail separates Inbox from Spam. Outlook has Focused versus Other, plus Junk. A foldering report maps exactly where you landed across all of them.
What makes foldering reports genuinely useful is context. Landing in Promotions at Gmail isn't necessarily a disaster (it's still technically the inbox), but it does affect open rates because most users check Promotions less frequently. Landing in Spam anywhere is urgent. Landing in Focused at Outlook is great. You can't tell any of that from a single aggregate number.
Foldering reports come from seed list testing or panel data, and the accuracy of what they show depends on how that data was collected. A foldering report built from a handful of seed addresses at each provider can miss personalization effects that real subscribers experience. Worth keeping in mind when you read the numbers.
If you're seeing an unusual split (lots of Promotions, or anything in Spam), our free Email Header Analyzer can help you understand what signals your messages are sending to filters.
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