1. A machine implemented method for content preparation or selection, comprising: receiving, as part of a content preparation or selection, by a content preparation or selection module operated by a computing system, a representation of a concept; and determining, for the content preparation or selection, by the content preparation or selection module, topical relevance of a content item (N) of a content hierarchy (C) to the concept; wherein the content hierarchy includes a plurality of content items, including N; and wherein determining topical relevance of N to the concept is based at least in part on interrelationships among at least some of other content items of the hierarchy other than N and its descendant content items, including interrelationships between N, an ancestor content item of N, and a sibling content item of the ancestor item of N.