2. A method for presenting reference information from a plurality of content sources related to content presented on a display, the method comprising: parsing the presented content for standard or non-standard taxonomy terms, the non-standard taxonomy terms being mapped to standard taxonomy terms when the non-standard taxonomy terms are synonyms to standard taxonomy terms, wherein if the presented content contains non-recognized taxonomy tags or no tags, then the presented content is parsed to identify any standard taxonomy terms contained in the presented content; searching, unprompted by a user, a normalized index for related content for at least one of the standard taxonomy terms, the normalized index indexing related content from the content sources; retrieving the related content; and displaying the related content.
2. A method for presenting reference information from a plurality of content sources related to content presented on a display, the method comprising: parsing the presented content for standard or non-standard taxonomy terms, the non-standard taxonomy terms being mapped to standard taxonomy terms when the non-standard taxonomy terms are synonyms to standard taxonomy terms, wherein if the presented content contains non-recognized taxonomy tags or no tags, then the presented content is parsed to identify any standard taxonomy terms contained in the presented content; searching, unprompted by a user, a normalized index for related content for at least one of the standard taxonomy terms, the normalized index indexing related content from the content sources; retrieving the related content; and displaying the related content. 3. The method of claim 2 , further comprising simultaneously displaying the related content and the presented content.