Essentially, you just refer new customers. They had 2 tiers, one for regular customers and one for people who wanted to
"build a business" out of it. In the regular customer tier, for every person you referred, you got a certain % off your monthly electricity bill. The "business builders" actually made commissions on customers signed up. Like any energy company in a de-regulated area, they have different products to choose from, just like if you buy through NRG or TXU.