A system and process for tracking users' usage of content in computer systems. The tracking and accumulation of content usage information allows content providers to understand more about their user base. In a computer system having numerous users, it is advantageous to provide relevant customized content in addition to any specifically requested content. By storing and processing content usage information for users in a computer system, customized content may be provided to a user based on the user's previous usage of similar content. In operation, a computer system hosting various content creates a unique identifier, having data storage space, for a given user of the computer system. When a user sends a request for content to the computer system, a unique identifier is created and/or updated with information relevant to a user's content request. The identifier is passed back to the user with the specifically desired content. When processing subsequent requests for content, the computer system updates the unique identifier with most recent usage information. In addition, the computer system processes the unique identifier for previous usage information in an effort to provide customized relevant content, in addition to the specifically desired content.