Enabling consumers to self-design unique products that match their idiosyncratic preferences is the key value driver of modern mass customization systems. These systems are increasingly becoming "social," allowing for consumer-to-consumer interactions such as commenting on each other's self-designed products. The present research examines how receiving others' feedback on initial product configurations affects consumers' ultimate product designs and their satisfaction with these self-designed products. Evidence from a field study in a European car manufacturer's brand community and from two follow-up experiments reveals that receiving feedback from other community members on initial self-designs leads to less unique final self-designs, lower satisfaction with self-designed products, lower product usage frequency, and lower monetary product valuations. We provide evidence that the negative influence of feedback on consumers' satisfaction with self-designed products is mediated by an increase in decision uncertainty and perceived process complexity. The implications of socially enriched mass customization systems for both consumer welfare and seller profitability are discussed.