Facebook is a social networking website founded in 2004 by Mark Zuckerberg. It allows users to connect with friends and family from around the world and share photos, articles, and updates. Some advantages of Facebook include it being free to use, enabling communication through chatting, and reconnecting with old friends. However, some disadvantages are privacy and security concerns like profiles being hacked or users being exposed to inappropriate content. Overall, if used for the right purposes and with caution, Facebook can be a useful social tool.