Don’t look at numbers or metrics in the abstract — total page views, logged in accounts, etc, but talk about users.
[…]
How many people are really using your product?
You need a metric that specifically answers this. It can be “x people did 3 searches in the past week”. Or “y people visited my site 9 times in the past month”. Or “z people made at least one purchase in the last 90 days.” But whatever it is, it should be a signal that they are using their product in the way you expected and that they use it enough so that you believe they will come back to use it more and more.