PHP：存储全局信息，以便所有其他用户可以访问它？

Is there a way that PHP can track and keep a data for what page is being accessed and then this piece of data can be opened/ accessed by all other computers/ users?

For instance, when I am inside my CMS and editing a page called 'home' then I want to store this data in a global (maybe??) so the front end users can know that this page is being edited.

I was thinking using $_SESSION in the backend,

$_SESSION['url'] = $_REQUEST['url'];

Then in the front end page that is being viewed by other person from another machines,

print_r($_SESSION);

and this could be the result,

Array
(
    [url] => home
)

Of course it does not work! Any ideas what I can do to store a global information so it can be accessed by all other computers/ users?