Lightning networking is a second-tier technology that uses micro payment channels to scale your block chain's ability to execute transactions more efficiently. Compared to those conducted directly on the bitcoin block chain (i.e., on the chain), transactions over lightning networks are faster, less expensive, and more readily confirmed.

In addition to decongesting the bitcoin block chain, lightning network transactions are designed to reduce transaction fees by taking them out of the main block chain. Lightning network transactions can also be used for out-of-chain exchanges of crypto currencies.
In addition, it is useful to facilitate atomic exchanges which allow one crypto currency to be exchanged for another without the involvement of an intermediary, such as a crypto currency exchange.

The Lightning Network is a second layer added to Bitcoin's (BTC) blockchain that permits off-chain exchanges, for example exchanges between parties not on the blockchain network. Different installment channels between gatherings or bitcoin clients make up the second layer.

The Lightning Network is a proposal for improving Bitcoin transactions. It would do this by creating a second layer on top of the Bitcoin blockchain that would allow transactions to take place much faster and with much less cost, opening up the possibility for more use cases. The Lightning Network is not yet fully developed or deployed, but many are optimistic that it will improve the use of Bitcoin as well as other cryptocurrencies in general.