Formula
New signups from viral touchpoint / Total exposures to touchpoint x 100
How to measure
Tag every viral touchpoint, such as a shared link view, and divide resulting signups by total exposures to that touchpoint.
Why track it
This metric shows whether the viral mechanic itself, not just its reach, is effective at turning exposure into new users.
Example
A shared-document viewer page converts 8% of non-user viewers into signups after adding a clearer call-to-action banner.