High quality Open Source Software (OSS) has been used in many commercial software developments. In order to provide technical support to end users, OSS projects manage a user mailing list. It is for discussion about bugs and new functions of OSS with end users. However, according to a survey of Japanese companies that use OSS to build their commercial software, the biggest problem is the lack of adequate technical support. In this study, we investigate what type of thread can get feedback in user mailing list. As a result of a case study using Apache and Python project data, a thread is posted by a deep experienced user would be received a useful answer. In addition, we found threads written about internal system information of the OSS is more likely to be replied.