There are only so many reasons a user will invite another person they know to use a mobile app. The user will only share an app if the user gets financial value, social capital, an improvement in the app experience, or altruism.

Financial value

Users will invite their friends to an app if the app pays them to do it, like how Instacart may give you $15 off your next order if a friend signs up for the service. An app can also gift a user a less physical part of their service, like how Dropbox gave people 5GB more free storage or how Wealthfront would manage an extra $10k for free if a user brought someone onto the respective platform. An app can also give discounts for a period time, or even shares of a stock in Robinhood’s case. These are all examples of a company incentivizes a user to share an app with friends with financial benefits.

Social capital

Many users will invite their social networks to use an app in an effort for that user to accrue social capital. They want to appear cool and hip, and want to be the “first” to invite someone to use an app. Additionally, people may brag to their social networks. By sharing a Strava post of your workout to Instagram, you are bragging to that network about your workout as much as you are inviting them to join you on Strava.

Mutual benefit by improvement in the app experience

A user will invite their network into an app if it improves the user’s own experience. For example, Facebook is boring without your friends on the platform; to make the platform more exciting for you, you’d invite friends to join you on Facebook.

Altruism

Lastly, a user may share an app with their friend altruistically. If they believe their friend will find an app particularly useful, a user will share the app in an effort to help their friend. For example, if a friend is particularly bad at investing, a user might share the Mint mobile app with them.