This window does just what it promises - shows the content that you are searching for. You can choose what modules are allowed in the search results. This way you can create separate search pages for you articles, products or videos.
Some of the modules in Cornerstone can combine content of "simplier" modules. Articles can contain videos, pictures and even questionnaire forms, that are stored in particular modules. Shop items can store pictures in the Images module, and articles in a linked article module.