15. The system of claim 14 , wherein each quantitative value defines one of: a sentiment of the author of the plain text content included in the element of textual data towards the subject attribute represented by the concept; or an occurrence of a question directed towards the subject attribute represented by the concept.
14. A system comprising: one or more processors; and computer storage media storing computer executable instructions which when executed perform a method for generating a multidimensional synopsis of a stream of textual data, the method comprising: accessing a stream of textual data that includes a number of elements of textual data, each element of textual data comprising plain text content that is associated with an author and is directed to a particular subject; identifying a first dimension and a second dimension for the stream of textual data, the first dimension including a number of concepts that each represent a subject attribute of the particular subject, the second dimension including a number of concepts that each represent an author attribute; generating machine learning classification training for the concepts in the first and second dimensions; for each of the number of elements of textual data, determining, using the machine learning classification training, which sentence fragments within the plain text content included in the element address a particular concept of the first or second dimension, and for each concept within the first dimension that appears in the plain text content included in the element, generating a quantitative value; identifying each intersecting set of concepts from the first and second dimensions; and for each intersecting set of concepts, generating a score from the corresponding quantitative values, the score representing a prevalence of the intersecting set of concepts within the stream of textual data.