If this is not an April Fools' joke, it would be interesting to know what miners are they using to achieve such incredible roi. Well, scrypt.cc would defend that they are trading altcoins, but what about the others 
I think they are ponzi.
I think they are ponzi.
Scrypt.cc is more ponzi then all of them together. 60 days ROI and you sell this to outsiders, yeah right.