rp024 - 7:14 pm on Feb 6, 2013 (gmt 0)
We do SEO. When we add this canonical tag
<link rel="canonical" href="http://www.mysite.com"/>
Google's indexing sees every single page on the host as "index" since all pages use the same dynamic header.
We want only the index to have the canonical variable to eliminate duplicate indexing. The rest of the pages in we don't want associated with the canonical at all so they get indexed properly.