What’s the “inbox memory effect”?

The inbox memory effect describes how past behavior creates persistent placement patterns:

Users who have consistently engaged create a positive memory. Future messages from that sender inherit inbox presumption.

Users who have ignored or marked spam create negative memory. Future messages face uphill placement battles.

This memory is sticky but not permanent. Sustained behavioral change can shift placement over time, but it takes consistent signals.

The harbor remembers how past shipments were received. That memory shapes how they greet your next arrival.