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.