Recommendations are crucial for the success of large websites. While there are many ways to de-termine recommendations, the relative quality of these recommenders depends on many factors and is largely unknown. We propose a new clas-sification of recommenders and comparatively evaluate their relative quality for a sample web-site. The evaluation is performed with AWESOME (Adaptive website recommenda-tions), a new data warehouse-based recommen-dation system capturing and evaluating user feedback on presented recommendations. More-over, we show how AWESOME performs an automatic and adaptive closed-loop website op-timization by dynamically selecting the most promising recommenders based on continuously measured recommendation feedback. We pro-pose and evaluate several alternatives for dy-namic recommender selection including a power-ful machine learning approach
