1. A method of organizing user reviews for data analysis, comprising the steps, each implemented in a computer system, of: (a) sampling a plurality of reviews to be analyzed from one or more sources; (b) identifying unique terms in each of said plurality of reviews; (c) determining frequency values indicating the number of times each of the unique terms appears in each of said plurality of reviews; (d) adjusting the frequency values for each unique term to account for the rarity of that unique term across the plurality of reviews; (e) calculating the similarities between the reviews based on the frequency values as adjusted in step (d); and (f) grouping the reviews into clusters based on the similarities of the reviews determined in step (e).