I see so many services offering to double, triple and multiple in all possible amounts the coins you put to them. This doesn't sound very convincing to me but some of them are offering the list of blockchain transactions as a proof that coins were credited. Is this pure scam like I think or is there a possibility to realy make some coins? Would like to hear your thoughts and experiences.
Doubling bitcoins has been spread-out in social media, I've almost seen it most of the time in facebook. These kind of sites that offering like this is obviously Ponzi scheme here is the link example of the scam site about in bitcoin
http://www.viral-alert.com/scam-site/ I hope this thing will give you some idea about the scam sites in this kind of industry.
I can see this doubling bitcoin is not a legit approach to anyone because most investments even in fiat money investments were resulting to scam people promising a ghost good profit which has double returns to your money. Oh no, I think thats an old version of scam which mainly known today a ponzi scheme and am sure its not a new term for all of us in this thread. These ways of scam id promising heaven to you which in reality a hell to your dreams and big profit loss. So if you wanted to double your bitcoins do it on your own proper ways, and put a hardwork on it.