Amazon associates, or affiliates, put a link on their Web sites directing customers to Amazon's Web site and receive a referral fee each time they direct business to the online retailer.
Amazon spokesman Bill Curry said he respected the groups' decisions, adding that EPIC and Junkbusters were just two of Amazon's 500,000 associates.
"The old policy had a provision that said we don't sell, rent, lease or share information with third parties [but that Amazon] may choose to do so in the future. That's a pretty broad statement with a lot of flexibility," Curry said, adding that Amazon isn't in the business of selling customer information to third parties.
Clare Haney of the IDG News Service contributed to this report.