"A system and method for evaluating documents for approval or rejection and/or rating.
The method comprises comparing the document to one or more criteria determining whether the document contains an element that is substantially identical to one or more of a visual element, an audio element or a textual element that is determined to be displeasing."
The document describes how Google might analyze text and audio files. For example, Google might use optical character recognition tools and pattern matching against image and sound databases.