A computer-implemented recommendation service uses item-to-item relationship mappings to select items to recommend to the user. The item-to-item relationship mappings may reflect user-behavior-based (e.g., purchase-based) item relationships, content-based item relationships, or a combination thereof....http://www.google.de/patents/US20110282758?utm_source=gb-gplus-sharePatent US20110282758 - ITEM RECOMMENDATION SERVICE
