Is Notification a Retention Product?

Active users can't always be defined with zero and one uses. What about nearly people who are active or are becoming active, if they use it one time last year and zero times this year? That's something that you need to define on how you count users in your growth metrics. On eBay, for example, let's say if you want to track active buyers, then you had to buy something just using it doesn't mean match for eBay,.