PBmining, also known as Piggy Back mining, was once the greatest cloud mining companies operating in the market. Offering dirt cheap rates for their GH/s, it attracted the attention of many with some users depositing over 10 Bitcoins to the site. Sure it gave a return on investment for some who had jumped on early but as of recent times it has encountered trouble. Many speculate the company was simply a Ponzi at heart but with the site promising refunds in January only time will tell…
source
http://www.btcfeed.net/psa/pb-mining/
