Which of the following is NOT typically included in email marketing metrics?

The selection of ad impressions as the correct answer highlights the specific focus of email marketing metrics, which are centered around the performance and engagement of emails sent to subscribers. Unique clicks, conversion rates, and unsubscriptions are all key metrics that help marketers evaluate the effectiveness of their email campaigns.

Unique clicks indicate how many individual recipients clicked on a link within the email, providing insight into engagement and interest. Conversion rates show how many of those email engagements resulted in a desired action, such as making a purchase or signing up for a service, which helps to measure the ultimate effectiveness of the email in achieving marketing goals. Unsubscriptions reveal how many individuals opted out of future communications, which can indicate the quality of content or targeting.

On the other hand, ad impressions relate to the number of times an advertisement is displayed, which is more relevant to display advertising rather than email marketing metrics. Email campaigns focus on direct interactions within the email content itself, making ad impressions irrelevant in this context.