I'm about to fall asleep here, so I don't want to read that tutorial..
What's the code supposed to do? Parse keywords from referrer info and print it on the html page?
edit: I read the class (title, keyword, page) stuff but from having done it on a fake tgp i built 10 months ago, it's not a very pretty solution. When you want to edit the page in an editor like dreamweaver, you can't, because the page code only says $page->show();. To edit the page layout, you'll have to edit the class function.
It's better imo to replace just parts of the html page with php (e.g.<P> today: <?php date("Y-m-d"); ?></P>) instead of doing something like $page->print_content();