Objective: This study explores the differences in mobile application usage between adolescents in Hong Kong and Mainland China, highlighting how these variances contribute to the formation of virtual parallel societies. Methods: The theoretical framework incorporates Walter Lippmann's Public Opinion and Eli Pariser's Filter Bubbles to explain how algorithm-driven platforms foster informational silos. The study employed a mixed-methods approach, primarily using secondary data from the QuestMobile 2023 China Mobile Internet Annual Report and data from the Department of the Government of the Hong Kong Special Administrative Region, along with qualitative research methods such as semi-structured interviews and content analysis of social media interactions. Results: The findings suggest significant disparities in app usage between adolescents in Hong Kong and Mainland China, influenced by technological, sociological, and political factors. Adolescents in Hong Kong preferred global platforms like Instagram and Facebook, while Mainland Chinese adolescents used local platforms like WeChat and Weibo. These differences were influenced by sociological factors, including class, education, and access to technology, and contributed to the formation of distinct informational silos. Conclusion: The differences in mobile application usage have led to the development of virtual parallel societies, with implications for national identity and socio-political cohesion. Policy recommendations include enhancing media literacy, promoting Chinese perspectives globally, and encouraging social media platforms that foster a shared national identity.