This study investigates how and why a specific speaker’s linguistic behavioral patterns may differ across channels on the same social media platform. Specifically, this research addresses important components in conversations, such as grammaticality and illocutionary indications, as well as the emoji feature that is exclusive to online media, the Chinese social media platform Sina Weibo in this case. Through comparing speakers’ comments between posts on the state-controlled People’s Daily Weibo channel and the “super-topic” free discussion forum on social, cultural, and political events, it is clear that the topics being addressed and the functions that different channels serve in each case, respectively, contribute to the speakers’ different perceptions of these channels. Additionally, from individual speakers’ responses in interviews during the study, the special censorship nature of social media in China and the exclusively superior accessibility of state-controlled media also complicate speakers’ linguistic choices, emphasizing their consideration of locating “safety” and practical usefulness on social media. As there remains limited previous research focusing on this specific area, this research hopes to offer new insights on exploring sociolinguistic ideologies embedded in Mandarin online communication.