This should only interest international buyers, like me from Singapore (Asia), who buys from Amazon Europe.
Amazon Europe has revised their international shipping charges to reflect weight of the parcels.
Here's a comparison before and after for shipping charges to Asia.
Amazon Germany
Before
Standard: €14 (box)
Express: €40 (box)
There's no per-item charges
After
Standard: €9 (box) and €4 per kg
Express: €28 (box) and €8 per kg
Amazon France
Before
Standard: €13 (box) + €1.90 per item
Express: €19 (box) + €1.85 per item
After
Standard: €13 (box) + €1.90 per item
Express: €20 (box) + €4 per kg
Amazon Italy
Standard: €14 (box) + €5 per kg
Express: €25 (box) + €5 per kg
Amazon Spain
Standard: €14 (box) + €4 per kg
Express: €20 (box) and €9 per kg
What does this mean?
As books are heavy, this means it's now more expensive to ship them from Europe, with the exception of Amazon UK. Amazon UK's shipping rate still goes by per-item so it's relatively affordable.
It looks like I have to think twice before buying any books from Europe, especially if they aren't sold elsewhere.