Originally Posted by GirlsOnYou

Redirect to some sponsor. Only show the redirect to some human visitors. Not to search engines. You already got up there with a blackhat method so you don't need to worry much whether it is safe or not as your sites are getting spam reports anyway.

$useragent = strtolower($_SERVER['HTTP_USER_AGENT']);

if(strpos($useragent, 'google') === false && strpos($useragent, 'msnbot') === false && strpos($useragent, 'yahoo') === false && strpos($useragent, 'ia_archiver') === false) $is_searchengine = false;
else $is_searchengine = true;

if($is_searchengine == false) header('Location: http://somesponsor.com/');