1. A computer process for generating behavior-based recommendations, comprising: generating, by a score generator, scores for individual users of a plurality of users of an electronic catalog that provides functionality for users to browse and purchase catalog items, said scores comprising a first component corresponding to purchase recency, a second component corresponding to purchase frequency, and a third component corresponding to amount spent; dividing the users into a plurality of segments based on the generated scores, wherein at least some scores correspond to different segments than other scores; for individual ones of the plurality of users, associating catalog items and/or catalog item attributes from a purchase history of the respective user with a particular segment of the plurality of segments, the particular segment corresponding to the generated score for the respective user; for individual segments of the plurality of segments, detecting, by a correlation detector, segment characterizing correlations between (1) the respective segment, and (2) particular catalog items and/or catalog item attributes associated with the respective segment, wherein detecting the segment characterizing correlations comprises searching for statistically significant correlations that differentiate particular segments from other segments; retrieving the generated score for a current user of the plurality of users; matching the current user's generated score with one of the plurality of segments; selecting, by a recommendation service, catalog items to recommend to the current user based at least partly on the detected segment characterizing correlations between the matched segment and particular catalog items and/or catalog item attributes; and causing the selected catalog items to be presented to current user via a user interface, thereby enabling the current user to more efficiently locate and navigate to representations of catalog items of interest; said process implemented programmatically by a computing system that comprises one or more computing devices.