You can create a ledger by POSTing to /ledgers at one of those 4 nodes and it will be replicated on the other nodes. The CLI is very rough at the moment but is probably the best place to see how to construct a valid message: https://github.com/hyperledger/hyperledger-cli/blob/master/b...
I think you mean the URL in the ledger creation command, e.g., 'hyperledger ledger register newcoin https://newcoin.com'. This would just be the official site of the asset or company, like bitcoin.org is for bitcoin. Currently, this is just used so people can get extra information, but it could be used in the future to remove spam currencies if there is no official site (although we would not be able to do this ourselves, it would require the consent of the entire consensus pool).
The service is currently running on four nodes:
http://hyperledger-staging-1.herokuapp.com http://hyperledger-staging-2.herokuapp.com http://hyperledger-staging-3.herokuapp.com http://hyperledger-staging-4.herokuapp.com
You can create a ledger by POSTing to /ledgers at one of those 4 nodes and it will be replicated on the other nodes. The CLI is very rough at the moment but is probably the best place to see how to construct a valid message: https://github.com/hyperledger/hyperledger-cli/blob/master/b...