A method and system for maintaining and delivering secure online content includes facilitating registration of secure content with an online content placement auction system, auditing the registered content to ensure security requirements for the registered content are met, and holding an auction among bidders for placement of content in a secure online content space. The process of holding an auction for the content space includes receiving a call for secure content to be served in the content space, transmitting a bid request to bidders in response to the call, receiving bid replies having bid amounts and proposed content to be securely served in the content space, and determining a qualifying subset of the received bid replies having proposed content approved as secure.