Human memory is generally poor and often fails in unpredictable ways, sometimes with dire consequences. On social occasions, it usually causes embarrassing situations (e.g., forgetting the name of a friend). Moreover, as the number of contacts increases, people feel difficult to maintain their social contacts with merely memory. Aiming at helping people better manage their social contacts, a powerful social contact management tool named SCM is introduced. It supports the auto-collection of rich contact data and a simple but efficient contact retrieval interface. First, an online survey is carried out with a series of questions about contact management. Based on the survey results, the SCM system is developed. Furthermore, to evaluate the usability and effectiveness of SCM, a user study of contact management is performed which proved SCM is very helpful for contact re-finding. On the other hand, several particular phenomena about social contact management and recall are discovered. The human contact-memorizing pattern is also concluded based on the result of this user study