The interviewer's question seeks a critical evaluation of a hypothetical scenario in which Pinterest's weekly active users (WAU) are on the rise, yet the open rates for email notifications are declining. This question is designed to assess your analytical abilities, problem-solving skills, and understanding of digital marketing. When tackling this question, it is essential to grasp the relevant terms: WAU stands for weekly active users. An increase in this metric indicates that more individuals are engaging with Pinterest each week. Email open rates represent the percentage of subscribers who open a specific email compared to the total number of subscribers. In this context, a decrease implies that fewer people are opening Pinterest's emails. To thoroughly address the question, consider possible explanations for this discrepancy. Reflect on factors such as changes in email campaign strategies, modifications to the Pinterest platform, or adjustments to algorithms. Subsequently, outline how you would investigate the issue to validate your assumptions or identify the underlying problem.