tedster - 3:34 am on May 16, 2008 (gmt 0) Official Google Blog [googleblog.blogspot.com]
Good approach, Webnauts! I haven't had cause to use an X-Robots-Tag since it was introduced in July 2007, and it completely escaped my mind. This is exactly the type of situation that the protocol was created for.
...META tags give you useful control over how each webpage on your site is indexed. But it only works for HTML pages. How can you control access to other types of documents, such as Adobe PDF files, video and audio files and other types? Well, now the same flexibility for specifying per-URL tags is available for all other files type.
Official Google Blog [googleblog.blogspot.com]