I am building a brochure-ware website for a company that sells products all across the world. They need the site to ask the user what region they are in before using the site; there are 5 regions. This is because there are different products offered to different regions and each region may or may not want to customize their own content. However, at launch and likely forever, most of the pages will be the exact same minus what is listed in the footer and in the product selection menu.
My question is how should I structure the sitemap for this site for best SEO? Should I be concerned with duplicate content penalties and/or cannibalizing the site's presence on the SERP?
A quick list of options I am considering:
www.example.com/page?region(no cookie, pages require the parameter. If visited without; the user must select a region)
www.example.com/page(using cookie and a splash screen if needed; could pass parameter in to set the region for direct linking)
site.com (top-page with links to regions top-pages) site.com/region/page site.com/region_lang/page
site.com (top-page with links to regions top-pages) region.site.com/page region_lang.site.com/page
Don't worry about duplicate content on product pages. You can have some regional varieties in additional text (by law), f.e. product/usage advices, advices for shipping and warranty and so on. Be a little creative. Little changes will be enough.
For the product listings you can use meta robots "noindex, noarchive, follow".
"The client does not want each region to have its own domain"
Then you need to talk some sense into your client.
site.com site.co.uk site.com.tr site.in site.jp
...that is the way to go.
They can all be very similar, or even the same. I've found that Google will not penalize the same company for having multiple domains with the same content.
If they all have to be on one domain, then you do site.com/en/controller/method/. Use a GET to parse the URL and call content based on language in the URL.
But getting your client to buy a domain for each country is better.
I work in multinational SEO pretty much every day. I'd advise this structure:
example.comas the "global" portal.
ch.example.com/de/for German in Switzerland,
ch.example.com/fr/for French in Switzerland.)
example.chon marketing materials for easier recognition and it will still work.)
Localise using a combination of hreflang sitemaps/meta tags/header responses (Google proprietary stuff), Google WMT localisation and canonical tags as appropriate.