We have 2 identical versions of our site - one on a .ca and the other on a .com. Both are identical, but for all the pricing and related shipping info, etc... as it relates to Canada.
Since the recent shift in GEO targeting our .com is no longer ranking on the Google.ca as it used to. We have a geo ip redirect on the .com so that if the user is from Canada they get redirected to the .ca site, if in US they get the .com.
Currently we are banning the engines from crawling and indexing the .ca version and I'm wondering if we should open this up to Google (and other engines) and if we did is there a possible dup content penality.
Having two identical sites is not a good idea. Two identical sites may cause a duplicity issue with the search engines. You may want to considerer making the sites unique.
Google may penalize both of your sites for this duplicate issue however usually google will pick the original site and apply the rankings to it. I've seen both cases, neither of which will give you the results you are trying to achieve. If you are going to keep both sites identical you are running this rick.
It's definitely good advice to try to differentiate the sites as much as possible with localized content.
For other discussions on these issues, take a look at the Geo-Targeted Search threads referenced in the Hot Topics area [webmasterworld.com], which is always pinned to the top of this forum's index page.
Is there any way to use the robots.txt to allow the .ca for .ca crawlers and the .com for .com crawlers? I don't recall if Google, Yahoo and MSN have country specific crawlers (I don't think so though...).
Right now we've got a complete ban for all engines on the .ca - the site's massive and making the copy unique would be a massive undertaking.
We could host the .ca version in Canada - but again, I don't think that'll help with the duplicate content issue.