Live: Live pages can be seen by anybody and by the search engines.
Draft: Draft pages can only be seen by logged in CMS users. Draft pages cannot be seen by non-logged in visitors, nor by the search engines.
Hidden: Hidden pages can be seen by non-logged in visitors. They can be accessed by anyone with a link or the page URL. Hidden pages automatically have a robots.txt file and therefore can not be seen by the search engines.
If you only wish to view 'Live' pages, highlight only 'Live' and click 'Search.
Similarly, you may wish to view only pages that are 'Draft'. You can then highlight 'Draft', deselect 'Live' and click 'Search'.
It is common to search for 'Section' pages that are 'Hidden', you can do this here by selecting 'Section' and 'Hidden' and then clicking 'Search'. You can actually filter by any combination of search criteria at once.