Huh, no. YAML is a superset of JSON. So valid JSON is valid YAML. This is sometimes suprisingly useful. Also, YAML is used everywhere and like the other user pointed out, has mature well tested libs for almost every language.
That's false. http://p3rl.org/JSON::XS#JSON-and-YAML
This YAML:
user:
name: Ted
is equivalent to this YAML: user: {"name": "Ted"}
which is equivalent to this YAML/JSON: {"user": {"name": "Ted"}}Basically take JSON, make quotes optional for strings and make curly brackets optional if the object is indented properly, and boom you've got (something like) YAML.