I think the funnel for this onboarding step can be a really simple single event that is sent when the tooltip is shown, and contains the appInstallID. That way, we can measure whether a user is more likely to share a fact after being shown the tooltip, versus no tooltip shown.
@KLans_WMF I'd be happy to meet with Dbrant to help with this. This is a good opportunity to loop in any other person from the team who will be doing data analysis. This way, we can make sure that the team can answer questions like this that require less research and more data analysis. @KLans_WMF does this sound good? If yes, who are the other people in the team I should loop in?