Facebook is a social networking site with over 64 million users that was created in 2004 at Harvard University. It allows users to add friends, share photos and events, chat, and use applications. While it has benefits like staying connected with friends, it also has disadvantages like wasting time, privacy concerns, and potential cyberbullying. The presentation recommends that parents supervise children's use of Facebook by joining their network, limiting personal information shared, and monitoring activities to keep children safe online.