Viral Loops - Viral Loops is a viral and referral marketing platform to launch ranking competitions, sweepstakes, pre-launch and referral programs.

Stack Exchange - Stack Exchange is a fast-growing network of 84 [and counting] question and answer sites on diverse...

Referral Candy - Run a fully automated, customizable and easy to integrate referral program for ecommerce.

Reddit - Reddit gives you the best of the internet in one place. Get a constantly updating feed of breaking news, fun stories, pics, memes, and videos just for you.

InviteBox - Acquire new customers with a social referral program. InviteBox is a flexible referral marketing solution that brings you new customers at no cost.

Product Hunt - A website that lets users share and discover new products