Social networks allow people to connect and share information online. They have evolved from basic forums and blogs to complex sites like Facebook and Twitter. Some key facts about social networks include that they allow people to meet new friends, find old friends, and connect with others who share similar interests or problems. However, social networks also present safety risks like cyberbullying and stalking that require users to be cautious about sharing private information online. Popular social networking sites in India include Facebook, WhatsApp, Instagram, and LinkedIn.