This document discusses social networks, including what they are, who uses them, popular networks like WhatsApp, Instagram, Twitter, Facebook and YouTube, as well as advantages and disadvantages. It notes that social networks allow people to connect with friends virtually and share content. The most popular networks are used mainly by young people for entertainment. There are different types of social networks including horizontal networks for all users, vertical networks for specific audiences, professional networks, and networks for leisure, universities, news, blogging, microblogging, and sharing content.