Heh. "Started" in this case means "started hacking on the compiler". overview.pod is a roadmap of the compiler code, not a document about what is and is not implemented, how to use it, etc. In the past, the "user volume" has been small enough that "read the code" or "look at the examples" has been the "documentation" for what is and isn't implemented. There should probably be a list of what does and does not work somewhere. As for the language itself, here are links to the apocalypses and exegeses, which reflect almost all knowledge of Perl 6 outside Damian's and Larry's heads. If you try to run many of the programs and snippets therein, they will break, hopefully with an informative error message (like "parse error in the following statement"), informing you that those parts of the language are not yet implemented.

/s