19. A computer-implemented method for generating recommendations of unique items, the computer-implemented method comprising: receiving an input from a user that comprises user-expressed preferences associated with a plurality of unique items; calculating, using a computer system, a customization score for each unique item in the plurality of unique items, the customization score at least partially based on at least one customization attribute associated with that unique item; calculating, using the computer system, a condition score for each unique item in the plurality of unique items, the condition score at least partially based on at least one condition attribute associated with that unique item; generating, using the computer system, a dissimilarity penalty for each unique item in the plurality of unique items by combining the customization score and the condition score for that unique item, the dissimilarity penalty at least partially generated based on a magnitude of dissimilarity between the unique item and the user-expressed preferences; and generating, using the computer system, a recommendation of unique items by ranking at least a portion of the plurality of the unique items based at least partially on the calculated dissimilarity penalties; wherein the computer system comprises a computer processor and electronic memory.
19. A computer-implemented method for generating recommendations of unique items, the computer-implemented method comprising: receiving an input from a user that comprises user-expressed preferences associated with a plurality of unique items; calculating, using a computer system, a customization score for each unique item in the plurality of unique items, the customization score at least partially based on at least one customization attribute associated with that unique item; calculating, using the computer system, a condition score for each unique item in the plurality of unique items, the condition score at least partially based on at least one condition attribute associated with that unique item; generating, using the computer system, a dissimilarity penalty for each unique item in the plurality of unique items by combining the customization score and the condition score for that unique item, the dissimilarity penalty at least partially generated based on a magnitude of dissimilarity between the unique item and the user-expressed preferences; and generating, using the computer system, a recommendation of unique items by ranking at least a portion of the plurality of the unique items based at least partially on the calculated dissimilarity penalties; wherein the computer system comprises a computer processor and electronic memory. 20. The computer-implemented method of claim 19 , wherein the unique items comprise one of the following types of items: used automobiles, existing homes, real estate, household goods, customized electronics, customized goods.