Even if you can reuse, aggregate or share that photo, video, meme or text, should you? Our mixed-methods study explores the legal and ethical issues involved in content-sharing practices in social media and messaging apps through analysis of public policy challenges, related work in Human-Computer Interaction (HCI) literature and quantitative and qualitative data. Key concepts in the study include copyright law, plagiarism, user-generated content (UGC) and fair use