Considering that the YAML spec rivals XML in complexity, I doubt it. Between that complexity, incompatible parsers, intentional loose types...what do you really gain?

YAML will never be a sane format for machines to talk to each other. There are just too many ways to interpret it. It's not even really a good human-readable format.

Maybe something like TOML? It's very human-readable and simple. But it's not a very good serialization language.