This document provides an overview of social media platforms YouTube, Snapchat, and Instagram. It discusses their purpose, content, target users, sources of revenue, legal/ethical issues, and advertising approaches. YouTube was founded in 2005 as a video sharing site, aiming to connect people through sharing appropriate information with followers. Revenue comes from ads, with creators earning $7.60 per 1000 views on average. Legal issues relate to copyright enforcement. Snapchat and Instagram also aim to facilitate sharing between users, but focus on photos/videos. They generate revenue from ads and have similar copyright/Terms of use policies.