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.
I know you are talking about those HYIPs sites out there and Doublers, yes it is true that they are going to double your bitcoin in time, but there are risks on this thing if you are going to invest your bitcoin on them. Most of the time, after they have launched their project within a week, or if they know that many bitcoin users have already invested on their site or project, they will run off with all the bitcoin that's been invested to them without you guys noticing it.
Rather than investing it to something like that, you might just want to save and hold your bitcoin and wait until its price go up again higher on its higher price before so you can get a huge profit from it, than taking the risk to invest it on the HYIPs out there.