CloudSponge is described as 'contact picker that imports all the major address books. Websites use our product so that users don’t have to type email addresses into their referral forms to send an invitation, greeting card or coupon'. There are five alternatives to CloudSponge for a variety of platforms, including Online / Web-based, BSD, Self-Hosted solutions, SaaS and Mac. The best alternative is OpenInviter, which is both free and Open Source. Other great apps like CloudSponge are AdiInviter Pro (Paid, Open Source), SaaSiter Contacts Importer (Paid), Super Tell A Friend PRO (Paid) and SocialInviter (Paid).
The ultimate contacts importer and tell-a-friend system for your website. AdiInviter Pro allows your website visitors to import and invite their contacts to your website from Google, Facebook, Twitter, Yahoo, Outlook, Linkedin and many other services.
Super Tell A Friend is a powerful script that lets you implement word of mouth marketing campaigns directly on your website. The only tell a friend script with rewards, reminders and follow-up emails. Yahoo, Hotmail, Gmail Contact Importer And Classic Tell A Friend Script.