1. A method comprising: receiving, at a content delivery system, a content bundle comprising a plurality of content blocks for assembling modular invitational content and rules for dynamically assembling the modular invitational content for a user terminal by combining blocks from the plurality of content blocks in the content bundle based at least on preferences and properties associated with the user terminal, wherein the rules are provided by a content provider to define how to assemble the modular invitational content for the user terminal based on the preferences and properties; delivering, based on the content bundle, the modular invitational content to the user terminal to yield delivered invitational content, the delivered invitational content comprising selected content blocks from the plurality of content blocks assembled based on at least one of the rules, the preferences associated with the user terminal, or the properties associated with the user terminal; and after an analysis of a user response to at least a portion of the selected content blocks in the delivered invitational content, modifying the content bundle based on the analysis of the user response.