This document provides information on various social media platforms, including their audiences, how people use them, how brands use them, key performance indicators, and content types. It summarizes Facebook as the most established social channel with broad global reach, though its audience is becoming more niche. YouTube is owned by Google and is the second most popular search engine, where people watch billions of hours of video per month. Twitter was started by a high school dropout and is now owned by Yahoo, and is used to curate content that provides a window into users' personalities and interests. Instagram prioritizes community growth and has very high engagement rates relative to other channels.