To get the navigation bar on the left to be consistent across pages without huge amounts of replacation, server side includes are used. Some experts have claimed that server side includes are slow or insecure. It's likely that these claims are true only under unusual circumstances. They might be slow if they are turned on for all html pages. That is, the pages must be examined by the server for include directives even though most pages don't have any such directives. These pages use the .shtml file name extension, and the server only processes includes for files with this extension. The security concerns must be because server side includes can execute code on the server. However, the shtml files themselves are not generally writable by the end user, so with reasonable care, security is not an issue. So, they remain an issue if the administrator thinks that the shtml writer is either incompetent or malicious. My ISP (Internet Service Provider) allows them. I use them at home. I have seen ISPs that allow arbitrary Perl code on the server, but do not allow server side includes. What is it that they are thinking? Perl is the diesel powered Swiss Army Jackhammer of solutions, with overhead that makes server side includes appear to have the same overhead as normal static html pages, which appears to be true by all other measures.