YAML is a popular data serialization language known for its simplicity and human-readability. It is widely used in configuration files, data persistence, internet messaging, and cross-language data sharing. YAML stands for "YAML Ain't Markup Language" and works with all modern programming languages. The basic syntax of a YAML file includes three node types: maps/dictionaries, arrays/lists, and literals (strings, numbers, boolean, etc.). Comments can also be added using the '#' character. Advanced YAML features include documents, schemas, tags, anchors, aliases, and overrides. Tags can be used to explicitly specify a type for values. Anchors (&) and aliases (*) help avoid duplication in large configurations by defining a chunk of configuration that can be referred to at different parts of the configuration. YAML is a superset of JSON, meaning all JSON files are valid YAML files, but not vice versa. YAML is used in various tools such as Kubernetes and Ansible for automating deployment, scaling, and management of containerized applications.