No que tu postaste, do index.template.php:
<meta http-equiv="Content-Type" content="text/html; charset=', $context['character_set'], '" />
<meta name="description" content="', $context['page_title'], '" />', empty($context['robot_no_index']) ? '' : '
<meta name="robots" content="noindex" />', '
<meta name="keywords" content="PHP, MySQL, bulletin, board, free, open, source, smf, simple, machines, forum" />
<script language="JavaScript" type="text/javascript" src="', $settings['default_theme_url'], '/script.js?fin11"></script>
Muda o PHP, MySQL, bulletin, board, free, open, source, smf, simple, machines, forum para keywords relacionadas com o teu fórum.