Embodiments are provided for importing contacts. A contact importer leverages the various contacts associated with a user of a content management service to find potential new users and/or customers. A contact importer may run on one or more devices of a user associated with an account on a content management system, and import various contacts of that user to a contact list. The list may be culled to weed out non-human contacts, and processed so as to assign an affinity score to each contact, expressing a degree of affinity to the user. Incentives may be offered to the user for either sending or approving an invitation to a contact to register with the content management system, paid upon the invitee successfully registering. Different incentives may be offered for an accepted invitation from various contacts or classes thereof.