1. A computer system configured to provide an online media exchange, the computer system comprising: a web server configured to provide a user interface to advertisers and publishers accessing the online media exchange; one or more application servers configured to manage data objects associated with respective advertisers and publishers and further configured to manage online negotiations between advertisers and publishers regarding placement of advertiser ads on publisher websites; a database in communication with the one or more application servers, the database storing data including the data objects; and one or more ad servers in communication with the database, the one or more ad servers configured to serve data defining advertiser ads to publisher websites.