SaaSiter Contacts Importer - Allow users to import contacts into their system.
Referral Candy - Run a fully automated, customizable and easy to integrate referral program for ecommerce.
OpenInviter - OpenInviter is a free import contacts (addressbook) script from email providers like Mail2World...
Ambassador - Referral Automation, Made Simple.
AdiInviter Pro - The ultimate contacts importer and tell-a-friend system for your website.
ReferralRocket.io - Referral Program Software for SaaS