Topic-model based Estimation of Passive Twitter-User's Interests from Followed Users' Tweets

User modeling based on the contents of social network services has been developed to recommend information related to the preference of each user. Most of the previous studies have analyzed active users' tweets and estimated their interests. Meanwhile, although there are more than a certain number of passive users, who do not tweet but only gather information, little research has been conducted on interest estimation for them due to the lack of clues for estimating their interests. In this study, we developed an interest estimation method for passive Twitter users from the tweets of followed users by applying an interest topic extraction method for active users. In our evaluation, we confirmed the effectiveness of the proposed method by comparison with simple topic extraction methods based on data with interest topic evaluation of 12 users.