Each activity or route from GO can be configured to be private or public.
This privacy state is shown by a little padlock in the title bar.
By default, files are private.
When the 'share' button is pressed, this file will be set as public. This means that it will be accessible by a link, which can be shared where users wants (Facebook, Twitter, Whatsapp, email...).
It is possible to modify the privacy configuration of a file from the edition window..
If a link to a file has been shared, and then it is set as private, the link will stop working.