If you set a component to global scope, it is accessible to all users across multiple sessions. For example, multiple users might simultaneously access an input form that updates a NewPerson component, initially set as follows:

$class=Person
name=Bill
age=28

If the NewPerson component has global scope, each user can update the values of this component from their respective browser sessions, and thereby overwrite changes posted by other users. In general, in an application that is accessed by multiple users, components like this are set to session or request scope, in order to guarantee data integrity and consistency within the current session or request.