How do bounces relate to engagement filtering?

Bounces and engagement are complementary reputation signals:

What each measures:

Bounces: Technical validity of addresses. Engagement: Recipient interest and response.

Combined signal:

High bounces + low engagement = very poor list. Low bounces + low engagement = valid but unwanted mail. Low bounces + high engagement = healthy list.

ISP perspective:

Both indicate sender quality. Engagement increasingly weighted in filtering. Bounces are more binary; engagement is continuous.

Interaction effects:

Sending to invalid addresses wastes engagement potential. Disengaged subscribers may become bounces (account abandoned). Both should be managed together.

Holistic list health:

Address validity is necessary but not sufficient. Engagement shows addresses want your mail. Both metrics matter for deliverability.

Valid addresses that ignore you are only slightly better than invalid ones. Engagement completes the list quality picture.