genesis-mining is an old legitimate website to earn bitcoin. It returns bitcoins but in a very slow way. The payment method is credit card, bitcoin and so on. There are two contracts available and they are :
1. yearly basis
2. lifetime basis. 

If you invest money for yearly basis, then there is a high chance of losing money. And if you invest money on lifetime basis then you can earn money over life time. 
And there is a chance to increase your earnings on genesis-mining which is increasing the hashpower. 
   For more information go to :  http://www.gensis-mining.com