After our recent system upgrade, the simple URL format has been
changed. Older formats will still work, but you should start using
the new format.

If you would like to link directly to an item’s detail page using a
text link, you can use the following format to construct your links:
http://www.amazon.com/dp/ASIN/ref=nosim/?tag=your_Associates_ID
Replace ASIN with the 10-digit ASIN/ISBN of the product,
and “your_Associates_ID” stands for your Associates ID. The
text, “ref=nosim,” is what allows your visitor to be taken directly
to an item’s detail page when the link is used.

Although the above format can be used to construct your links, we do
recommend that you use our Build Links tools at
http://associates.amazon.com. These tools will automatically insert
your Associates ID into the HTML code, which allows us to correctly
track sales from your links and will present you with images and
product information where applicable.

I hope this information is helpful. Thank you for participating in
the Associates Program.