What does the '90-10' rule in email length suggest?

The '90-10' rule in email length advocates that 90% of emails should be concise while allowing 10% to be longer and more detailed. This principle emphasizes the importance of brevity in email communication, acknowledging that recipients often prefer quick, clear messages that get to the point without unnecessary fluff.

In a practical context, adopting this rule helps maintain engagement, as shorter emails are more likely to be read and acted upon. The longer emails, constituting the remaining 10%, can be reserved for situations where detailed explanations are necessary, such as project updates or complex information that cannot be condensed. This balance ensures efficient communication while still accommodating certain situations that require additional context.

The other choices suggest either a uniformly long email length, which could lead to disengagement, or imply arbitrary length restrictions that do not align with effective email communication strategies. Some even present misleading interpretations of how to manage reading engagement, which can detract from the overall goal of effective email marketing.