By design, every "page" (which, depending on the namespace, may be called an article, help, project, template, user, etc., page) created on a wiki has a place for a corresponding "discussion" page (more commonly referred to as the "talk" page).
The purpose of Talk page is to provide an appropriate, relevant place for:
- feedback and comments about the associated page;
- discussion that another editor or group may want to associate with the page; or,
- any other information that needs to be associated with the document page.
...all, in lieu of, and without having to modify the associated page.