It is where every terminal program can be published as a website.
To better explain, this allows you to share terminal based outputs with the world without needing to press run each time. All you will need to do is grab the url link from the web window and share it with the world.
An example of an application to try this out on would be any terminal based game.
You can find more information in regards to this here
All you need to do is follow these easy steps: