Big time doubts, too high rate and no explanation what will they do with the money.
actually there is an explanation on the site if you checked it out. and someone even explained it above your comment
http://i.imgur.com/Cgugb23.jpg
now lets talk about whether it is a Ponzi scheme or if it is going to be the run away plan.
It is not Ponzi scheme. @wetsuit show in public their Bitcoin mining address, their power and pools where they are mining.
You can read about that in Freebitco.in main thread:
https://bitcointalk.org/index.php?topic=320959.msg18109501#msg18109501
Maybe the mining farm that they say is the sign that freebitco.in will scam people soon and how could a site offer such long time profit while they cannot give any strong facts that they can sustain their site for such a long time, 1 year waiting is to much for unsure situation and surely if we will used our bitcoin properly we will gonna earn double from it in 1 year time span. But for now i will just stay away from them since i don't see any legalities from them.
Yes, they could show us their mining farm pictures. But I must say their site is working fine since some years ago and never scammed anyone. Also you don't need to let your money there for one year, the interest is paid daily and you can withdraw it anytime.
You could try to double your BTCs in one year, but I think it's too risk, as all legit investments don't offer much interest percentage. With gambling the risk is high also.