Here is a pretty good link explaining a bit more: https://www.quora.com/How-is-Hyperledger-different-than-Ripple . It doesn't appear to require a currency to run the ledger, just uses a "consensus process". It is a very interesting project that we are following to determine if there will be opportunities for DNotes. I've signed up for the mailing list: http://lists.hyperledger.org/mailman/listinfo