Common elements of site are in one place and included throughout the site
Useful to include documents or information that is used repeatedly throughout a site, such as common headers, footers, and navigation elements. You can change these chunks in one place and have an effect on the entire site!
Documents (or parts of pages) that change often
Useful to include documents or information that change frequently; only the "included" file needs to be updated, not the page itself. Also the person or program editing the file need only have permissions to edit the "included" file, not the actual HTML document that includes it; only the data in the "include" file needs to be written, not the entire HTML page.
Document Information
Useful to include information specific about a document, such as last modified date, URI, size.
