Actually, this isn't -quite- true... you're supposed to use a 304 Moved Temporarily message, with a Location: header. For browsers that don't grok 304, you can include a Content-Type: text/html that can include HTML in the output, with a link to where you want them to go. (It also works with Refresh: 0;URL=filename.html headers too.)

Just like Perl, There's More Than One Way To Do It.