Can you calculate how much he get from publicity per roll compared to how much he gives away?
Too many unknowns, do you want to start a similar faucet? 
I can tell you probabilities of payouts, and therefore average payout from one roll (without referrals):[0 - 9885]: ~ 1/20000 + 9885/10000 = 0.98855
[9886 - 9985] ~ (9985-9886+1)/10000 = 0.01 (~ once per 100 rolls)
[9986 - 9993] ~ (9993-9986+1)/10000 = 0.0008 (~ once per 1250 rolls)
[9994 - 9997] ~ (9997-9994+1)/10000 = 0.0004 (~ once per 2500 rolls)
[9998 - 9999] ~ (9999-9998+1)/10000 = 0.0002 (~ once per 5000 rolls)
[10000] ~ 1/20000 = 0.00005 (~ once per 20 000 rolls)
sanity check: 0.98855+0.01+0.0008+0.0004+0.0002+0.00005 = 1
average payout (using values right now): (0.98855*0.00000438)+(0.01*0.00004376)+(0.0008*0.00043764)+(0.0004*0.00437637)+(0.0002*0.04376368)+(0.00005*0.43763676) = 0.00003750 BTC
Whoa, that's much bigger than I thought, but math checks out, it seems.
Thanks for the calculation! Average return of 3750 per roll and people may do 10 banner impressions in average because of the multiply game and 1000impressions need to earn him 0.00375 not counting what he gets back with the multiply game, what he gives to refs and costs, that's a lot to get from 1000impressions
1.5millions impressions get them 5.5BTC on bitcointalk atm : https://bitcointalk.org/index.php?topic=526958.0