Activation rate is the percentage of new users who reach your product's "aha moment", the first action that makes the value real. Not just signing up, not just logging in, but actually doing the thing that demonstrates what your product does.
What counts as "activated" depends on your product. For a task manager, it might be completing a first task. For a feedback tool, it might be receiving and responding to a first piece of customer input.
Why it matters more than signups
Signups are easy to inflate with a good ad or a free trial. If those users don't activate, they'll churn, and the growth is temporary.
A low activation rate usually means users aren't hitting value fast enough, there's too much friction before the payoff, or the wrong users are signing up in the first place.
How to improve it
Define your activation event precisely, then measure how many users reach it within their first session, day, and week. Work backward to find the drop-off point.
You can connect behavioral patterns to the feedback users leave in FeatureOS Boards to understand where and why they're getting stuck.