.COM vs .CA rankings - .CA ranks on Google.com

[HarborOneBank]

Hi SEOMOZers,

We have a fairly large retail client with both .COM and .CA domains.  Each of the sites are almost identical in design and, in most cases, content (these would be product pages).  The .US site has been live for nearly 2.5 years while the Canadian probably over a year younger or so.  Both sites are hosted in the US.

What we're starting to see as of the last few months are searches that used to rank .COM product pages now rank the Canadian page above the US page on Google.com.  We've checked Webmaster Tools for each site and they target the appropriate country.  With nearly all examples we've seen, we haven't noticed any more links pointing to the Canadian page, and where this is becoming a widespread occurence we're not convinced it's a linking issue.

My question is why Google might see both versions but rank the Canadian page above the US page on Google.com for a search being performed in the US?  Does anyone have any ideas on why this may be happening?

[HarborOneBank]

Thanks for the suggestions, Darren - we did discuss this as a possible reason and we plan on testing this theory out.

[Whitespark]

If the content pages are identical, then my guess is that it's based on Google's discovery date of the pages. Google sees the pages as duplicate content, and tries to rank the original source above the duplicate. So, in those cases where the .ca page is outranking .com page, Google's crawler just happened to pick up that page and add it to the index before it came across the same page on the .com site.

You could try adjusting the crawl speed in webmaster tools. Make the .ca site slower and the .com site faster. Not sure how much Google abides by these settings though. A better solution would be to stagger the publishing of new product pages. Have them appear on the .com site first and let them simmer a few days, then publish on the .ca site.

This is just a theory, but hope it helps!

Darren