SMX Advanced Session Synopsis: Duplicate Content Solutions & The Canonical Tag

Synopsis of the Duplicate Content/Canonical Link Element session at SMX Advanced. Written in real time format.

Canonical Link Element:

-Flag Duplicate Content
--HTML tagging
--Embedded in head section of web page
--Treated as Internal 301 redirect

-Announced in 1st Quarter of this year by the "big 3"

What is the Canonical Link Element Good For?

Its best purpose is to revitalize interna discussions about site architecture. The canonical link element is a way to "virtually" eliminate duplicate content.

Canonical tag passes page rank and anchor text.

Use link canonical when dealing with faceted pages: example would be if you have pages where the same product or service has multiple url's.

Canonical tag is not only about removing duplicate content, but recovering leaked page rank.
-Noindex or disallowed pages in robots.txt still build page rank.
-Canonical tag can be used to pass this page rank to the desired target url

301 redirect is favored, but canonical tag can be used in a pinch.

Rel=nofollow will stop flow of internal page rank to non-canonical versions, but does not address existing page rank (i.e. from third party sites, also does not prevent the page from being indexed.

Page rank leakage can occur in each of these situatios: robots.txt exclusions, meta robots noindex, rel=nofollow, xml sitemap exclusion. Canonical tag can correct this (but is still not preferable to 301); except 301's can affect sort capabilities.

**Canonical tag does not work from one domain to another, but may work between subdomains.***

Affiliate URLs
-rarely do they pass page rank or seo;
-run affiliate program in house and use 301 and/or canonical
-some affiliate links will pass page rank, but still should be run in house

Nofollows should not be used to exclude duplicate content, canonical tag should be. But there is some bit of heated discussion on the panel right now about this! Others say nofollow can be used for page rank sculpting..but Nathan Buggia at Microsoft just gave a warning about algorithm adjustment to compensate for nofollow page rank sculpting!