From scrolling Instagram Reels and following influencers on Xiaohongshu to engaging in vibrant discussions on LIHKG, social media is central to how we express ourselves, interact with others, and make sense of the world. This course offers a sociological deep dive into the digital platforms we use every day, connecting classic and contemporary theory with hands-on research tools. Students will explore how platforms shape self-presentation, community, and cultural trends, while critically engaging with issues such as platform governance, algorithmic control, and misinformation. Topics include influencer economies, online identity, meme cultures, and global/local social media practices. Through individual and collaborative projects using real-world social media data and digital analysis tools, students will gain both conceptual understanding and practical research experience.