The current study aims to explore the characteristics of feedback, relevant to learner-centered web-based learning. On web-based learning, the traditional understanding of feedback, concerned with its evaluative attributes, needs to be replaced by an approach to transactional feedback. The transactional feedback is likely to be a part of dialogue. A case of the web-based learning, in which interactions were activated through forum, indicated the characteristics of transactional feedback as followers: First, it gives feedback on task, affectation, and learning strategies, which functional mainly to evoking motivations and stimuli. Second, a tutor consistently and regularly provides the summary feedback on learning activities and so encourage transactional feedback based on deep empathy. Third, it is supported by co-constructive learning environments such as a number of small tasks, which are playing roles of topics on the forum, and easy access to the form for continuous interactions. However, this research adopted a conventional frame of feedback to the analysis of transactional feedback, and this results a number of difficulties in revealing its characteristics in details. A qualitative tools for the analysis of transactional feedback needs to be developed in the following study.