Server Side Includes
Server Side Includes (SSI's) are a form of server-side scripting that enable dynamic content updates in web pages.
Server Side Includes are true to their name because they take the content of one file and include it in the content of another.
Why Use Server Side Includes?
Let's say you have a web site with 200+ pages and each of your site's pages has a navigation menu and some footer information (like the copyright date). Should you need to update the copyright date, or add a new link to the navigation menu, all you would have to do is update one file and all of the 200+ pages in your site will dynamically reflect the change. Cool!