How do engagement metrics affect inboxing?

Engagement metrics are increasingly central to placement decisions, especially at Gmail:

Positive signals: Opens, clicks, replies, moving from spam to inbox, adding to contacts, spending time reading.

Negative signals: Deleting without opening, marking as spam, ignoring consistently, unsubscribing.

Providers track these signals at both sender and user levels. High engagement tells the algorithm that recipients want your mail.

The shift toward engagement-based filtering means list quality and content relevance directly impact placement.

Ships that bring cargo people actually want get the best dock assignments. Ships with unwanted goods get anchored in the back lot.