Monthly Active Users (MAU) is a metric that measures the number of unique users engaged with a startup's product or service in a given month.

It is a widely used benchmark for measuring the growth and engagement of a startup's user base and is often seen as a key indicator of the company's success.

For example, a social media startup might report its monthly active users as a way of demonstrating the size and engagement of its user base.

A growing number of monthly active users can indicate strong user engagement and a growing customer base, which can help to attract investment and drive future growth.

Conversely, a decline in monthly active users can be a red flag, indicating that the startup is struggling to retain its users or that there are issues with the product or service that need to be addressed.