GroovyDoc aims to provide Groovy what Javadoc provides for Java.
You can generate Groovy Documentation with Intellij or using the Gradle Groovydoc plugin.
The Grails folks were experimenting performance issues and they have developed a new Gradle plugin.
Instead of generating the docs in the same JVM as Gradle, which is prone to cause conflicts and place strain on the memory consumption of the Gradle process, this plugin will fork a separate JVM for Groovydoc generation
I think this plugin was heavily pushed to fruition during Gr8Conf hackengarten. Kudos to @graemerocher!