Signed-in users can easily share their projects at any time with others by just copying the URL from the browser and sending it over message/email or putting it in a blog or document.
When anyone visits the shared URL they will be able to see the code and execute commands. If the second user changes the code then the project will be forked from the first user's version into a clone for the second user. Any changes made after the forking will be not affect the first user's version.
This enables users to share their projects with others and lets others make changes and execute without affecting their own copy.
This is ideally suited for sharing your project in StackOverflow, blogs, articles or over email/messaging to your colleagues and friends.