Empowering users of flea market apps through the use of AI

Abstract

Secondhand trading apps promote reuse by enabling individuals to sell unwanted items and purchase usable or collectible goods. Unlike conventional e-commerce sites dominated by professional sellers, these apps connect individual buyers and sellers, making platform support crucial. This paper examines advancements in AI, including large language models that offer contextual understanding, natural language processing, and emotion analysis. Such technologies can automatically generate product descriptions, propose negotiation strategies, and facilitate effective communication, reducing transaction-related anxiety. We present case studies from the “Value Exchange Engineering” project—a collaboration between Mercari and The University of Tokyo—focusing on two aspects: presenting desired communication styles for negotiation support and developing “EmoBalloon,” a system that visually conveys emotional arousal in text chats using speech balloons. Our findings highlight AI’s potential to empower user interactions in online marketplaces.