Not quite sure about the usefulness of this tool, but it sure represents lots of work. Work your way through the script of Hamlet, pointing out other literary references to the text. For instance on one hand you've got James Joyce making use of the text "For this relief much thanks." But later in the same scene, linked to the line "Not a mouse stirring", we find a Charles Schultz reference to Sally reading "The Night Before Christmas" and coming to the "Not a creature was stirring, not even a mouse" line.
The site appears wiki-driven, so the entries are all from users trying to help. I appreciate the attempt, but like I said, not really sure what you'd *do* with it.