**Abstract**

Since 2020, we have faced drastic changes in our lives due to the pandemic. This caused a big paradigm shift in working styles. Parallel careers or multiple jobs are getting more common, and people are ascertaining their own competencies. The utilization of personal knowledge will continue to accelerate and this study sheds light on its societal value; the other side of sharing economy. Aoki (2021) revealed that participation in knowledge sharing has a significant positive impact on contributors' well-being. Those findings are more pertinent as utilization of personal knowledge increases under the ongoing paradigm shift in work style, and the expansion of C-to-C business. However, the reason for the correlation between knowledge sharing and well-being has not been identified. Thus, this study explores this issue by carefully examining knowledge-sharing contributors and their experiences. Finally, this study finds that contributors increased their well-being by deepening their knowledge and experience via competitive co-creation. Furthermore, their concerns shifted towards passing on their knowledge and experience to the next generation. Stakeholders of this study's results are those who utilize personal knowledge. For example, policymakers who wish to shed light on people with hidden potential, managers of knowledge-sharing platforms, such as crowdsourcing, marketing managers who collaborate with consumers, employers who wish to motivate their employees, and so on.

**Keywords:** user innovation, co-creation, social welfare, positive psychology, PERMA
