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 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, wherein determining the frequency values includes generating a term/review matrix having a plurality of rows and columns, in which each row identifies a review and each column identifies a unique term, and wherein the matrix specifies the frequency values for respective unique terms; (d) adjusting the frequency values for each unique term to account for the rarity of that unique term across the plurality of reviews, wherein adjusting the frequency values includes normalizing the values in the matrix based on values associated with the rarity of the unique term across the plurality of reviews being analyzed; (e) calculating 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).