You earn 50% of the house edge of every bet they make, whether they win or lose.

Here's some scenarios:

1 referral deposits 1 BTC, makes 1 bet for the whole thing, and cashes out or loses.
- You earn 1 BTC x 50% x 0.1% = 0.0005 BTC

1 referral deposits 1 BTC

• Bets 0.1 BTC and wins 0.1 BTC
• Bets 0.1 BTC and loses 0.1 BTC
• Repeats the above 100 times

- Total bets: 0.2 x 100 = 20 BTC (Even though he deposited only 1 BTC)
- You earn 20 BTC x 50% x 0.1% = 0.01 BTC

10000 referrals make no bets at all
- You earn nothing

If your referrrals are responsible collectively for 100,000 BTC of bets over the next year
- You earn 100000 BTC x 50% x 0.1% = 50 BTC
- 50 BTC / year is an average person's salary =D

Does that help clear things up for you?