9. The system of claim 8 , wherein suspending distribution of the other sponsored content item that has not been identified as likely containing malware comprises suspending an account of an advertiser associated with the other sponsored content item that has not been identified as likely containing malware.
8. A system comprising: one or more computers and one or more storage devices storing instructions that are operable, when executed by the one or more computers, to cause the one or more computers to perform operations comprising: determining that a sponsored content item has been identified as likely containing malware; identifying features of a landing page of the sponsored content item that has been identified as likely containing malware, wherein the sponsored content item directs a content viewer to the landing page in response to a selection of the sponsored content item; identifying features of another landing page of another sponsored content item that has not been identified as likely containing malware; determining that the features of the landing page of the sponsored content item that has been identified as likely containing malware are similar or identical to the features of the other landing page of the other sponsored content item that has not been identified as likely containing malware; and based on determining that the features of the landing page of the sponsored content item that has been identified as likely containing malware are similar or identical to the features of the other landing page of the other sponsored content item that has not been identified as likely containing malware, suspending distribution of the other sponsored content item that has not been identified as likely containing malware.