Er... (Score 5, Insightful)

From their current privacy policy here:

Use of Third Party Service Providers: We may, from time-to-time, employ other companies and individuals to perform functions on our behalf. Examples include sending e-mail and analyzing data. They have access to personal information needed to perform their functions, but may not use it for other purposes.

Business Relationships with Third Parties We Do Not Control: We work closely with some third parties. In some cases, we will include offerings from these businesses on A9.com. In other cases, we may include joint offerings from A9.com and these businesses on A9.com. Click here for examples of co-branded and joint offerings. You can tell when a third party is involved in the offering, and we share customer information related to those transactions with that third party.

My Amazon history + my credit card number + my web searching history (all searches are saved on A9 servers) + Amazon's stated intent to share information with third parties = a little too close to home for me. No thanks, A9... I'll stick with the relative anonymity of Google.