Stigma,

That is another way to do it and, it certainly has its advantages. However, it puts an additional load on the server because it requires .shtml files for the SSIs and has to parse each one before it can fulfill the browser's request for the document. For one or two documents, that probably doesn't hurt much but for all documents, it can make your site appear sluggish.

I used to use SSI a lot on my original web site but soon discovered, it was more of a hassle than it was worth. Now, everything is in non-parsing .html files.