In Viral Loops for Shopify, participants of your campaign can win in two ways:
by referring others to subscribe to the campaign
by referring others to make purchases at the store
A referred subscriber is counted when a referred friend joins the campaign using the Viral Loops widget in your store (or from the Referral Page). In this way the Referrer's referral count goes up and they win when they reach the milestones you have set.
A referred purchase is counted when the referred friend does the following:
Follows a referral link to the store
Makes a purchase (they don't need to subscribe to the campaign widget for the referred purchase to be attributed to their referrer.
For each referred purchase, the referrer wins the discount code you have set-up. They receive it via the "Successful Referral Email" that you can also edit from the Campaign Wizard.
Do you have any other questions? Let us know!