A header is automatically added on top of each content URL, but its not relevant for search and messing up the all the results beeing the first line of every page (in the code its the last line but visually its the first, which google is able to notice)

Solution1: You could put the header (content to exculde from google searches) in an iframe with a static url domain.com/header.html and a <meta name="robots" content="noindex" /> ? - are there takeoffs of this solution?

Solution2: You could deliver it conditionally by apache mod rewrite, php or javascript

-takeoff(?): google does not like it? will google ever try pages with a standard users's useragent and compare?

-takeoff: The hidden content will be missing in the google cache version as well...

example: add-header.php:

<?php  
$path = $_GET['path'];
echo file_get_contents($_SERVER["DOCUMENT_ROOT"].$path); ?>

apache virtual host config:

RewriteCond  %{HTTP_USER_AGENT}  !.*spider.*  [NC]
RewriteCond  %{HTTP_USER_AGENT}  !Yahoo.*   [NC]
RewriteCond  %{HTTP_USER_AGENT}  !Bing.*    [NC]
RewriteCond  %{HTTP_USER_AGENT}  !Yandex.*  [NC]
RewriteCond  %{HTTP_USER_AGENT}  !Baidu.*   [NC]
RewriteCond  %{HTTP_USER_AGENT}  !.*bot.*   [NC]
RewriteCond %{SCRIPT_FILENAME} \.htm$ [NC,OR]
RewriteCond %{SCRIPT_FILENAME} \.html$ [NC,OR]
RewriteCond %{SCRIPT_FILENAME} \.php$ [NC]
RewriteRule ^(.*)$  /var/www/add-header.php?path=%1 [L]