1. A method for searching a database of information, the database of information comprising information related to a plurality of content units, the information related to the plurality of content units comprising a plurality of stored annotations related to the plurality of content units, the plurality of stored annotations having been generated by processing the plurality of content units using a first semantic interpretation engine, the first semantic interpretation engine processing the plurality of content units according to at least one annotation model, the method comprising: receiving a query; determining at least one query annotation relating to the query by processing the query using a second semantic interpretation engine, the second semantic interpretation engine processing the query according to the at least one annotation model, wherein the at least one query annotation comprises a first query annotation, wherein the first query annotation comprises a semantic label for the first query annotation and content of the first query annotation; and searching the database based at least in part on the first query annotation, wherein the at least one annotation model of the first and second semantic interpretation engines defines at least one annotation type and, for each annotation type of the at least one annotation type, a semantic label for the annotation type and a format of content for the annotation type, wherein the semantic label for an annotation type defined by the at least one annotation model describes a meaning of content of an annotation having the annotation type in context of a content unit from which the content was extracted and that is annotated by the annotation, wherein each stored annotation of the plurality of stored annotations is of an annotation type of the at least one annotation type and annotates a content unit of the plurality of content units, each stored annotation of the plurality of stored annotations comprising the semantic label for the annotation type of the stored annotation and content that was extracted from the content unit that the stored annotation annotates and is of the format defined by the at least one annotation model for content of the annotation type, wherein each query annotation of the at least one query annotation is of an annotation type of the at least one annotation type, each query annotation comprising the semantic label for the annotation type of the query annotation and content that was extracted from the query and is of the format defined by the at least one annotation model for content of the annotation type.