YAML - The Bad
     
     * Started in April 2001 (over 8 years ago)
       * Still not rock solid
       * JSON was 2005 and quickly solid
     * Many Incompatible Implementations
       * YAML.pm, Syck, XS, Perl, Tiny
     * Very complex specification
       * 1.2 specification is not released yet
       * No implementation (not even libyaml) fully matches the 1.2 spec
     * Terrible vim syntax highlighting