This document provides an overview of social media platforms YouTube, Snapchat, and Instagram. It discusses the purpose, content, target users, sources of revenue, legal/ethical issues, positive/negative effects, advertising, and viral marketing capabilities of each platform. YouTube is described as a video sharing site where users can upload videos and connect socially. Snapchat is a multimedia messaging app focused on sharing photos and videos. Instagram is a social network for photo and video sharing owned by Facebook. The document outlines key aspects of how each platform operates and generates revenue.