This library can be used by CGI::Session to serialize session data. It uses YAML, or the faster C implementation, YAML::Syck if it is available. YAML serializers exist not just for Perl but also other dynamic languages, such as PHP, Python, and Ruby, so storing session data in this format makes it easy to share session data across different languages. YAML is made to be friendly for humans to parse as well as other computer languages. It creates a format that is easier to read than the default serializer.