Yes.

SSI (Server Side Includes) are directives that are placed in HTML pages, and processed on the server while the pages are being served. They let you add dynamically generated content to an existing HTML page, without having to serve the entire page via a CGI program, or other dynamic technology such as a Content Mangement System (CMS) or information coming from a database.

The decision of when to use SSI is usually a matter of how much of the page is static, and how much needs to be recalculated every time the page is served.

SSI is a great way to build consistency into your website so all content uses the same fonts & styles. SSI can also be used to add small pieces of information, such as the current time or stock quotes.