i think almost all of investments is scam 
after they get at they're quota they will become a scam like other investments scam :3 i think that we can't risk at investments because they will stole your btc they will let you profit low and they will get your high balance.
Yes specially in bitcoins mostly all of the investement schemes are scam if not all.And its better not to invest anywhere your bitcoins and just to hold or either spend them in different places rather than investing in ponzi and scam sites which gonna run with your money one day. after they get at they're quota they will become a scam like other investments scam :3 i think that we can't risk at investments because they will stole your btc they will let you profit low and they will get your high balance.an scam investment means an investment which was legit at first like a real business, a casino or an exchange service for example and then suddenly one day they ran away with all the money people invested in their business.
with that definition, the scam investments were so small so far because out of all the legit businesses only a handful have gone under.