There is provided a system and method for an ontological and rules based segmentation engine for networked content delivery. There is provided a segmentation engine for use by a network accessible computing device providing customized content for a user on the network, comprising a user context regarding the user, a content management system for storing content, a controlled vocabulary categorizing content, an ontology using the controlled vocabulary for referencing the content of the content management system, segment definitions grouping users into segments matching content types to controlled vocabulary elements, segment rules using user context to associate with segment definitions, and a segmentation processor. The segmentation processor can receive a content request from the user, and by using the elements of the segmentation engine, determine the segment definitions applicable to the user and provide customized content from the content management system. The segment definitions are readily modifiable without detailed low-level knowledge.