Strange Cross Domain Canonical Issue...

[AMHC]

We have 2 identical ecommerce sites. Using 301 is not an option since both are major brands. We've been testing cross domain canonicals for about 2 dozen products, which were pretty successful. Our rankings generally increased.

Then things got weird. For the most part, canonicaled pages appeared to have passed link juice since the  rankings significantly improved on the other site. The clean URLs (www.domain.com/product-name/sku.cfm) disappeared from the rankings, as they are supposed to, but some were replaced by urls with parameters that Google had indexed (apparently duplicate content). ex: (www.domain.com/product-name/sku.cfm?clicksource?3diaftv). The parametered URLs have the correct canonical tags.

In order to try and remove these from Google's index, we:

1. Had the pages fetched in GWT assuming that Google hadn't detected the canonical tage.

2. After we discovered a few hundred of these pages indexed on both sites, we built sitemaps of the offending pages and had the sitemaps fetched.

If anyone has any other ideas, please share.

[RyanPurkey]

You might want to make use of the URL Parameters section in Crawl >> URL Parameters to further help with your canonicalization. See: http://searchengineland.com/google-lets-you-tell-them-which-url-parameters-to-ignore-25925. Cheers!

[AMHC]

Thanks Ryan. The problem is that the URL parameters are created to track clicks from a hero image on our home page. If we block those parameters, we are wasting link juice in a big way.

[RyanPurkey]

Yes, you'll still have the tracking parameters in place for your own uses but when it comes to GWT and the crawler you'll be telling them that page_X+parameterY is the same as page_X+parameterZ. Your link juice would be more concentrated in that case as you wouldn't be creating duplicate content via parameters and would further help Google to canonicalize your page.

[LDS-SEO]

I experienced a similar issue recently. Upon closer inspection I noticed there were duplicate canonical tags on the pages. Google actually ignores ALL if there are more than one. So I would certainly double check that.