1. A computing device for storing video files comprising: a processor; a network interface for communicating with an external structured knowledge data source; a semantic metadata module; and a memory storing: a topic map table having a topic field and a topic type field; and a keyword list including a first set of keywords and a second set of keywords, wherein the semantic metadata module creates the keyword list and stores semantic metadata relating to a video in the topic map table; wherein the first set of keywords is extracted from existing metadata having a natural language format in a narrative form, said extracting of the first set performed using natural language processing, wherein the second set of keywords is extracted from the existing metadata, the second set having a tag list format, said extracting of the second set configured to extract keywords from a tag list with delimiters and from a tag list without delimiters, wherein keywords from the tag list without delimiters are in a one-word combination, a two-word combination, or a three-word combination, wherein a relevance rank is assigned to a keyword in the first set and to a keyword in the second set, such that relevance rank assigned based on a keyword source, such that a keyword from the first set is given a high relevance rank if it is from a title or a description and is given a low relevance rank if from a comment, wherein when a keyword is from the second set, the tag list format having delimiters, the keyword is given a medium relevance rank and when a keyword is from the second set without delimiters, the keyword is given a relevance rank dependent on a number of words comprising the keyword, and wherein the relevance rank of a duplicate keyword is increased.