My friend told me about x2coin.byethost5.com yesterday, I tried it and was very happy. But when I tried to double my btc second time they did not do it. I even tried a different btc address from a different pc (different ip address) with no success. Not that I am very greedy, but I just want to understand how they know that someone doubled before already. My friend also had no success second time, though it worked the first time for both of us. Also, how do they manage to giveaway so many bitcoins? is it all donations or do they mine like freebitco.in does ?
Most probably they are just ponzi scheme site. They will pay you from the money of those newly registered users. A lot of them is all over the sites nowadays advertising their ponzi scheme. Also, if they can double your coin then why offer it to others when they can have it all. They are just attracting those people who are greedy enough to believe that there is a possibility to double the coins in such a short amount of time. If it is too good to be true then most probably they are scam. If they pay you at first then it is just their strategy so that they can attract more investors and they can get away with bigger amount of coins.
