Cross Domain duplicate content...

[AMHC]

Does anyone have any experience with this situation?

We have 2 ecommerce websites that carry 90% of the same products, with mostly duplicate product descriptions across domains. We will be running some tests shortly.

Question 1:

If we deindex a group of product pages on Site A, should we see an increase in ranking for the same products on Site B? I know nothing is certain, just curious to hear your input.

The same 2 domains have different niche authorities. One is healthcare products, the other is general merchandise. We've seen this because different products rank higher on 1 domain or the other. Both sites have the same Moz Domain Authority (42, go figure). We are strongly considering cross domain canonicals.

Question 2

Does niche authority transfer with a cross domain canonical? In other words, for a particular product, will it rank the same on both domains regardless of which direction we canonical? Ex:

Site A: Healthcare Products, Site B: General Merchandise. I have a health product that ranks #15 on site A, and #30 on site B. If I use rel=canonical for this product on site B pointing at the same product on Site A, will the ranking be the same if I use Rel=canonical from Site A to Site B? Again, best guess is fine.

Question 3:

These domains have similar category page structures, URLs, etc,  but feature different products for a particular category. Since the pages are different, will cross domain canonicals be honored by Google?

[BradyDCallahan]

First of all, these are great questions.

My first question would be are the sites hosted on the same server or near-same IP address? If they are, and given much of the content is duplicate, chances are Google/search engines already understand these websites are somehow related. This is just something to consider...

Answer #1: If you de-index a group of products on one website, chances are, yes the other site would see some improvement just based on there being one less competitor. But I would do some extensive competitive research first to see if how the other sites are ranking next to your two sites.

Ultimately, I would side with a cross-domain canonical over de-indexing that way you're passing some value from one site to the other. I would do this on a product by product basis however, making sure the product niche you keep indexed matches with the site's overall niche theme and not vis versa.

Answer #2: My second paragraph sort of addresses your second question. Think from a semantic and topical understanding perspective here: if it's a healthcare product, make sure the site with the healthcare niche is the one being indexed, not just the general merchandise website. Even simply from a branding and general marketing perspective that makes more sense, IMO.

Answer #3: It sounds like, if there's duplicate descriptions (I'm guessing images, headers, and other content pieces) the canonicals likely would be honored. Even across domains, duplicate content can be a concern (especially if they're hosted together). Remember though, canonical tags are just a mere suggestion, so it could take some time for Google to honor it, but from the information you've given, I think that's your best shot.

Another thing to take into consideration when using canonical tag: make sure you're placing the canonical tag on the page/website that's performing worse of the two. There may be exceptions based on the niche and from a semantic perspective, but in general, you don't want to hurt your own performance by referencing the less authoritative page.

Good luck! Hope my advice helps.

[AMHC]

Brady:

Thanks for your advice. We are de-indexing as a test to see if our rankings are somehow being constrained because of duplicate content. Our rankings are not reacting as they should to our link building efforts, and I believe that duplicate content is the issue. With this test, I am trying to understand how Google sees and connects these 2 sites. If Google does connect the sites, then we must canonical since Google won't let us have 2 slots on page 1 for the same KW. If Google doesn't connect the sites, then we can theoretically get 2 listings on page 1 if our content is unique.

My hypothesis is that our massive duplicate content is having a negative impact on rankings. Google might be hitting us with a minor Panda slap, or the competing content is somehow hurting us algorithmicly. If we deindex a competing page, if we are being hurt by the algo, the remaining page should make a bump up.

I am pretty certain that canonicals will have a positive impact on our rankings. The question I am testing for is "do we have to canonical"? If we don't, then we have a decision to make - do we try to rank both sites for a KW, or canonical and focus on 1.

[BradyDCallahan]

If the alternative is just de-indexing those duplicate pages on one website, then I'd definitely recommend the cross-domain canonicals, yes.