Furthermore, for security reasons, Site pages are not allowed to run inline code and are marked as not to be compiled. This is done, in-part, so a person with database administrator access cannot place malicious code in a Site page. As a whole, site pages will make up the majority of the pages in a SharePoint site. They are the main pages used by users and designed to be manipulated my users. The next section on Application pages and their differences will cover more on the differences and why.

So, in short, and following the information above, an un-customized Site Page that can be stored as a template and combined with data from the content database is called ghosted, so long as it is not customized. If this page becomes customized to the point that the whole page must be stored in the database, it is called un-ghosted. Site pages tend to use the ~/_masterurl/default.master pages to maintain a consistent look and feel.