Hey Peter,

I am attempting to add the HTTP Header for PDF Files.  I really feel that this can be a bonus for sites that do have duplicated PDF content, especially on large e-commerce based sites.

I figured that they(Bing) didnt support it, and it sounds like it is probably not considered in the form of an HTTP Header

I may have to consider conditional logic and/or create a dynamic robots.txt file to disallow these PDF files for all other search engines, while serving up canonical HTTP Headers for Google, assuming that Bing doesnt support it.

It would be good to try and test, I may just end up doing that

I think you guys are confused.  There is a difference between the rel="canonical" HTTP header, and a rel="canonical" tag.

I understand their stance with regards to the tag, but wonder if they even consider the canonical in the form of an HTTP Header.

http://googlewebmastercentral.blogspot.com/2011/06/supporting-relcanonical-http-headers.html

anyone know^