The Lightning Network is a payment system being developed for bitcoin. The Lightning Network hopes to contribute to overcoming some of the bitcoin blockchain’s payment scalability “problems”/costs. The system is currently in testnet, but has been used for a few transactions, and seems to work. It would be used as an off-chain protocol similar in some ways to XCP.
Basically, the Lightning Network will be a peer to peer system for making micropayments of digital cryptocurrency through a scale-free network of bidirectional payment channels without delegating custody of funds or trust to third parties.
The Lightning Network has the potential to dramatically reduce the cost and time of bitcoin payments, which would reduce one of the major criticisms of bitcoin payments in their current form. It would shift the debate about scalability away from the blockchain itself and onto services using the bitcoin blockchain’s core verification system. I have been expecting more initiatives like the Lightning Network to emerge. I also expect more hosted services and payments processors to emerge as volume on the most popular blockchains continues to increase. I believe these developments will have the impact of driving transaction volume back to main blockchains with the largest network effects as mediums of exchange such as bitcoins, and away from many of the other alt coins that attempt to solve the payment scalability problem in other ways.