I found this cool Web demo for Bitcoin's Lightning network, which demonstrates buying news articles with a Bitcoin Lightning-enabled web wallet on the testnet:
Lightning Web Wallet
https://htlc.me/
Demo site where you can buy news articles with your Lightning Wallet
https://yalls.org/
The idea behind the Lightning Network is to not record every small transaction on the blockchain forever, which is expensive, but to introduce a secure, routeable, trustless, decentralized, cache-like system which allows you to spend a preloaded amount for various small payments like for coffee or news articles, and only record the balance from time to time on the more expensive blockchain.
In theory a Lightning channel can also be used to transfer coins instantaneously from one exchange to another with very low fees.
A payment channel is if you will like a prepaid credit card, where you put a certain amount of Bitcoin into, and then you can spend that amount for small purchases without paying a large transaction fee every time you make a payment. In the long run, the hope is that such a system will also take some burden off the main blockchain and will make both on-chain and off-chain transactions substantially cheaper and faster.
Sounds great at least in theory, what do you think? In my opinion Bitcoin needs both off-chain and on-chain scaling solutions including continuous block size increases ;)