In our case the advertisement server simply broke down and delivered no advertisements at all. Access to the server caused Chrome to throw an "Error 330 (net::ERR_CONTENT_DECODING_FAILED): Unknown error" error while Firefox displayed "Content Encoding Error: The page you are trying to view cannot be shown because it uses an invalid or unsupported form of compression."
The server has now been re-installed, the vulnerability fixed and all traces of tampering removed. We apologize for any inconvenience.
-Jari Ketola
CTO, AfterDawn.com