Okay, so I just claimed some dogecoin from the faucet at freedoge.co.in, and I saw an ad advertizing "Cryptodouble.biz." Taking a closer look, I immediately realized that this could be a probable ponzi scheme, as they advertize doubling your bitcoin in 48 hours time! A quick search on who.is shows that the domain "cryptodouble.biz" was registered just yesterday!
Anyways, just wanted to give a heads up, proceed with caution!