Anonymity plays a crucial role in social interactions online. Recently, a new phenomenon has emerged on Chinese social platforms where users collectively adopt a uniform avatar and nickname ''momo'', thereby achieving anonymity. However, understanding such spontaneous collective anonymity within Chinese cultural and contextual factors remains limited since much of the anonymity research focuses on Western users. Yet, it is unclear how users perceive the usage of ''momo'', their motivations, and how using this collective anonymity impacts their social interaction. To answer these questions, we conducted interviews with 20 ''momo'' users. We found that the shared identity ''momo'' provides an additional layer of anonymity on identity-constrained Chinese social platforms. Users adopted ''momo'' to engage in more inclusive discussions and to balance anonymity and self-presentation. Moreover, this collective anonymity fosters connections and forms a meaningful group identity in a loosely organized community. We also identified the benefits and risks associated with this unique collective anonymity. This work makes significant contributions to CSCW and HCI research by (1) extending the knowledge of anonymity practices and privacy concerns within non-Western and mainly Chinese contexts. (2) advancing the work on anonymity models by revealing the dual role of the Momo identity in facilitating collective anonymity and community bonds. (3) providing design implications to support future social technologies in identity design and anonymous communities.

The conflict between the rapid iteration demand of prototyping and the time-consuming nature of user tests has led researchers to adopt AI methods to identify usability issues. However, these AI-driven methods concentrate on evaluating the feasibility of a system, while often overlooking the influence of specified user characteristics and usage contexts. Our work proposes a tool named SimUser based on large language models (LLMs) with the Chain-of-Thought structure and user modeling method. It generates usability feedback by simulating the interaction between users and applications, which is influenced by user characteristics and contextual factors. The empirical study (48 human users and 21 designers) validated that in the context of a simple smartwatch interface, SimUser could generate heuristic usability feedback with the similarity varying from 35.7% to 100% according to the user groups and usability category. Our work provides insights into simulating users by LLM to improve future design activities.

This paper reports an interview study about the practice of teenagers’ chat-based cosplay in China. Findings reveal the four primary motivations of the participants and their main practice in chat-based cosplay. We found that adolescents perceived character presentation and portrayal as a central aspect of chat-based cosplay and they devoted significant effort to refine their characters to achieve higher character consistency. We highlighted the positive feedback loop between social relationships and story creation in chat-based cosplay community. In addition, we identified the influence and negative experiences on adolescents in the chat-based cosplay community.