Permission to track

Subscribers can optionally provide permission for their email opens and clicks to be tracked. That permission can be set to:

Unknown
Yes
No

A subscriber's permission to track is tied to their email address, meaning it's the same for all subscriber lists they are on within the same client. If a subscriber changes their permission for one subscriber list, it will be updated for all lists they are on within the same client.

"Unknown" responses

A subscriber will have a permission to track response of "Unknown" if:

Your subscribe form didn't include a permission to track checkbox when they signed up.
You didn't include a permission to track response for them when you imported or added them to a subscriber list.
You set the consenttotrack value to unchanged when adding via the API, and the subscriber was new, or didn't previously have a permission to track response.

A subscriber with an "Unknown" permission to track response will be tracked until their setting is explicitly set to "No".

"No" responses

If someone subscribes to your list, but does not give their permission to be tracked:

Their opens will not be recorded or shown in reports, but they will still be included in the total number of subscribers sent to. As a result, your open rates may actually be higher than reported.
Their clicks will not be recorded or shown in reports.
They will not be included in segments or journey conditions that rely on tracked campaign activity or journey activity. Please note that our systems cannot differentiate between an absence of tracking data and no subscriber activity and this can impact inclusion in certain segments or journey conditions.
Their opens and clicks will not be taken into account for engagement segments. Depending on when they set their permission to "no", this means their engagement may eventually be classified as Unengaged, or lower.

If a subscriber has an "Unknown" or "Yes" permission to track response, and later sets their permission to "No", they will not be tracked from that point in time. However, previous reporting and geolocation data will remain.

Set and view permission to track responses

Permission to track is provided by your subscribers, if you choose to give them that option. It can be enabled on:

You can also include or change permission responses when you import or add subscribers, or when you add or update subscribers via the API.

View permission responses

To see a subscriber's current permission to track response, you can:

Export a subscriber list they are on, and include the permission to track responses.
View their subscriber profile, and check the permission to track response.

A subscriber profile, showing "Yes" for "Permission to track email activity"

Clashing permission responses

If you change an email address on a subscriber's profile, and it matches an address on one or more of your other subscriber lists, the permission to track responses may clash. For example, the profile you change might be set to "Yes", while another profile with the same email address might already be set to "No".

What permission response is chosen for that email address, across all lists, depends on the response in each profile. If the subscriber you changed has their permission set to:

No — The permission will be set to "No" for that email address across all lists.
Yes — The permission will only be set to "Yes" for that email address if it is not already set to "No" on your other lists. If it is set to "No" on your other lists, the profile you changed will also be set to "No".
Unknown — The existing permission for that email address across all your lists will be used, whether "Unknown", "Yes", or "No", overwriting the response for the subscriber you changed.