A content mediating server receives from a client device a request for a next content item to be selected based on a content event relating to a current content item. The content mediating server generates requests for content from content providing servers providing content of corresponding types, and receives from each content providing server a content table relating content events in a set of content events to content items. For each content event in the set, the content mediating server selects, from the received tables, a content item, generates a composite content table relating each content event in the set to the selected content item, and transmits the composite table to the client device. The client device, in response to an observed content event relating to the current content item, selects the content item in the composite table corresponding to the observed content event as the next content item.