As a matter of fact, our API powers our core services like our Contactive Caller ID app which has more than 1 million downloads in the Google Play Store with a consistent 4-5 star rating.
Additionally, if we identify a call, but the resolution has low confidence, the user will be prompted to vote it up or down. This feeds directly into our identity graph, recalculating in realtime the connections between identities and contact information.
We also use the client app to enhance the existing connections in our identity graph. Each edge in our graph has a confidence level, and by using the data available to the app we adjust and recalculate the confidence levels of our directory in real-time. We never publish data points like photos, notes, etc. from the address book of our users.