Server Side Includes (SSI) is actually a list of directives that will allow you to include the content of a text file within an HTML file. In this manner, you are able to add any kind of content to various web pages in your website and modify it by simply modifying one text file. You can additionally add the output of various scripts so that the current date and time, the IP address of the visitor or the attributes of some file show on your website. This will help you add in some dynamic content to static webpages, making the website more appealing to your site visitors and creating a professional look and feel. It will also be quicker to update this content compared to editing every static page one by one. If you wish to use Server Side Includes in your website, the web pages that include the content of any kind of file must be with extension .shtml.