Changes in Amazon Affiliate program

For some time, I've tried to make money with Amazon.com's affiliate program. The success has not been spectacular, as my readers have bothered to order only two books so far.

Now Amazon has decided to limit the associates' possibilities of making money with the program:

After careful review of how we are investing our advertising resources, we have made the decision to no longer pay referral fees to Associates who send users to www.amazon.com, www.amazon.ca, or www.endless.com through keyword bidding and other paid search on Google, Yahoo, MSN, and other search engines, and their extended search networks. If you're not sure if this change affects you, please visit this page for FAQs.

As of May 1, 2009, Associates will not be paid referral fees for paid search traffic. Also, in connection with this change, as of May 1, 2009, Amazon will no longer make data feeds available to Associates for the purpose of sending users to the Amazon websites in the US or Canada via paid search.

As far as I understand, this means that the Amazon Associates are not allowed to use Google Ad program to get more readers and potential customers. It seems that the affiliate program has worked too well and Amazon wants to cut the referral payments down by limiting the monetization potential of the program.

I hope that we won't next read that search engine optimization (SEO) is forbidden, as well.