Gmail and other ISPs run hidden tests on senders by moving emails from inboxes to spam folders after recipients mark them as spam. If you notice a previously read email suddenly in spam, the ISP is testing whether you'll notice and re-engage, using it as a probe to gauge your sender vigilance.
Have you ever had an email that you've read or looked at and then you lost it and then eventually you found it and it was in your spam box just sitting there even though you read it? Yeah, a couple times. So let me explain what's actually happening there. So they were testing you. You were part of a test blast, most likely from that domain. You send an email out, it lands in inboxes, everything's good. But then people start hitting spam on that email because people are unhappy and suddenly Gmail will literally pull out an email out of your inbox and put it into the spam box to see if you go back to look for it. They want to know if it's real. It's a test. Subscribe to the pod.
