Bibliobattle, which is a framework that supports information sharing by introducing books together among participants, has been spread all over Japan. We consider that the Bibliobattle possesses a filtering method that selects a recommendation book from enormous books by presenters. In this paper, we verify what kind of recommendation methods the Bibliobattle possesses when we regard it as a kind of recommender systems. Compared with baseline systems, including a keyword search system, a recommender system by content-based filtering, and that by collaborative filtering, the recommender system by the Bibliobattle is superior to them from the viewpoint of diversity, novelty, and overall satisfaction. In addition, this paper showed that is was superior to them from the viewpoint of explanation because of its characteristics of that the presenters introduce their favorite books together.
