What is lightning?
Instant & cheap bitcoin transactions.
How can I try lightning?
An easy way to try the lightning network. Just visit tippin.me and sign up. Use a bitcoin lightning wallet such as lightning-wallet on android. On iOS there is thin wallet but that is not yet opensource. Follow the instructions in the app you download to create a payment channel and send some satoshis to your tippin.me account.
Why is it useful?
You can pay by lightning on a growing number of websites.