1. A method comprising: storing in a database a first annotation and a second annotation, the first annotation relating to a first content unit and comprising a first semantic label and first content, the first semantic label comprising a term that does not appear in the first content and indicating a semantic classification of the first content, the second annotation relating to a second content unit and comprising a second semantic label and second content, the second semantic label comprising a term that does not appear in the second content and indicating a semantic classification of the second content, the semantic classification of the second content being different from the semantic classification of the first content, wherein the semantic classification of the first content indicates a meaning of the first content in context of the first content unit, wherein the first content does not explicitly appear in the first content unit, the term that indicates the semantic classification of the first content indicating a meaning of the first content in context of the first content unit from which the first content was determined, wherein the second content is a text excerpt of text of the second content unit, wherein the semantic classification of the second content indicates that the second content is an organizational and/or grammatical element of the text of the second content unit, wherein the storing comprises storing the first semantic label for the first annotation and the second semantic label for the second annotation in a first table of the database, and storing the first content of the first annotation and the second content of the second annotation in at least one second table of the database different from the first table.