Like others said, it is 4% yearly interest, compounded daily. Daily 4% would be a stupid idea and a red flag for being a HYIP ponzi scheme.. Yeah, they are legit so far. I mean they have been here for like more than 7 years maybe. Their main ANN thread has hundreds of replies and the owner is still active. So, at least for now there aren't any scam accusation against them so its good to use. What ever you invest is used for mining and their bankroll. They have a very high house edge and people do gamble using dice over there, so they eventually manage to cover your profits too. Just be careful not to but all your bitcoins over there.