As someone said before this sounds like a scam. The lotto company has a house edge of course. But, this lottery site is not that popular yet. They will have to make a lot of money + a lot of time to pay off big jackpots. Unless they have a lot of money invested which is highly unlikely.
Basically the lotto company is gambling that no one will get high jackpots. But, they can also choose the winning numbers.
http://www.easysurf.cc/lotodd.htmTotal combinations of 6 out of 40 numbers (order does not matter)
3,838,380
Chance of winning 10, 000.00 BTC Prize (6 out of 6) [I doubt they have this much money or will make this much]
(6/40)*(5/39)*(4/38)*(3/37)*(2/36)*(1/35) = 720 in 2,763,633,600 = 1 in 3,838,380
4,000.00 Prize (5 out of 6)
204 in 3,838,380 = 1 in 18,815.59
100.00 BTC Prize (4 out of 6)
8,415 in 3,838,380 = 1 in 456.14
5.00 BTC Prize (3 of 6)
119,680 in 3,838,380 = 1 in 32.07
0.1 BTC Prize (2 of 6)
695,640 in 3,838,380 = 1 in 5.52
Payout %=[ (1/3,838,380*10,000) + (204/3,838,380*4,000) + (8,415/3,838,380*100) + (119,680/3,838,380*5) + (695,640/3,838,380*0.1)] = 60.8450440 %
House Edge % = 39.15495600%
Avg Payout (If you bought every single combination) = 0.03042252 BTC
Makes sense
At first, I thought this site was a scam but, it seems this site could last forever if a few things are met
a) they have at least $110,000 in reserve (Jackpot) (they need to pay in 24 hours)
b) Enough hopefuls keep investing in this site
I'm not affiliated with BTCLottery in any way. If my math is wrong please tell me. I learned a lot calculating the odds. Actually I gave up and used the calculator in the website. I spent a lot of time researching and writing this report.
Check this thread to talk abotu the odds.
https://bitcointalk.org/index.php?topic=102894.0