For social network apps it is critical that users have as many as connections as possible so they got engaged with the app. This formula aims to improve that.
When you use Liquid's Formulas, you'll select the audience, the action and the time.
Users with less than 5 friends
Send an In-App Message suggesting to connect to more people
Next time a user uses the app
Define a custom segment with users that have less that 5 friends.
Select In-App Message as the action and include a button that sends the user to the “Invite friends” page of your app.
Select “Send now” so that the next time the user opens the app receives the message