Please don't just detect, just allow selection. I always browse .com first because it has the most reviews. Tech books often have 0 reviews on .co.uk (which is idiotic but Amazon treats its different sites as entirely separate entities).
Better still would be the ability to select user country / language rather than have that decision taken for me. I am in Portugal and would like to be able to select my Amazon locale to be either the UK or USA and not my local Amazon site which is in France.
EDIT: Just change .com to .co.uk and you'll get the same page on Amazon UK. Sadly the exchange rate seems to be $1 = £1 - at least for the few books I checked.
What is the practical difference for you between the sites? Do the books ship faster and cheaper for .co.uk? I wonder why wouldn't Amazon's backend just figure it automatically and just ship locally anyway.
I spent a good deal of effort on the issue of Amazon locales for my book web app. There are quite a few reasons for this:
* Some books will exist in one locale but not in others;
* Some books will be in stock in a locale but not in others;
* Some books will have a different cover and/or slightly different edition if it's a UK or USA version;
* If you are buying the Kindle version, availability varies by country, but only UK residents can buy from the UK Kindle store.
* If you buy many books from the States and you live in the UK, you'll end up paying hefty import charges.
* Delivery from your closest Amazon is usually faster (provided the books are in stock) and free (or cheaper for expedite shipment).
If you go to the Staff Picks of the Week section of my site (http://anynewbooks.com/staff-picks/), you'll notice how under each book I'm forced to place up to 5 links (US, Canada, UK, Kindle international, UK Kindle). It may be slightly confusing, but in my experience international readers appreciate the effort (the rest of the world is quite sick of US only web apps to be frank).
I originally posted that I thought books were exempt from charges, but then saw someone right below had already said (and with more certainty than me!).
Sorry, probably should have either left it there or deleted it entirely.
Oh OK, no worries. My comment went from many upvotes to several downvotes, because people assumed that you were saying that my information was redundant and should be removed. We got to experience a bit of a hive-mind on HN. :)
One other reason to be make sure you cover locales properly, from the developer's point of view, is that you need separate Associates accounts for the different locales.
If you refer someone to the UK store then they eventually end up on the US store to buy then you won't get the sale (afaik).
I don't think .com will even ship to .ca (unless it's changed recently).
Why they don't merge it all? No idea, but I'd guess media owners have different locale ownership structures so they only acquire distributions rights for an X-based company shipping to customers-in-X, and so on.
I live in Canada and I've ordered from amazon.com for many years, 2001 is the earliest I could find.
Having said that, I only have ordered books from amazon.com, perhaps you are referring to ordering something else beause amazon.com has shipped to Canada for atleast the past 9 years.
You don't need to pay import duty on books imported into the UK because they're exempt (and zero-rated for VAT). It's solely a matter of shipping costs.
Not just that, but the product selection is different. For instance, I cannot buy my Joachim Witt CDs from amazon.com, I have to order from .de. I could not order some products from .ca and needed to use.com.
Granted, I haven't used amazon in about 3 years, they may have improved their global database system.
