A content delivery system for generating personalized content for a user. The system maintains an interest graph that shows the user's current attachment to one or more topics. When a user performs an action, a topic is determined for the action and the user's interest graph is modified based on the action. The system also receives content and analyzes the language of the content to determine a topic of the content. A similarity between the user's interests and the content is determined. The content is also analyzed to determine the popularity of the content. The user's interest level and the popularity of the content are then used to provide the user with a personalized content, such as a content recommendation or enhanced content.