A federal congressman is taking Amazon to task over concerns about the Kindle Fire's privacy protections.

Rep. Ed Markey (D-MA), the co-chairman of the Congressional Privacy Caucus, said in a statement Tuesday he was unhappy about Amazon's answers to a letter he sent to the Seattle-based retailer last month asking about Amazon Silk, a web browser installed in the Fire tablet.

Specifically, Markey wanted to know what type of information Amazon was planning to collect from customers, what Amazon planned to use with that information and what Amazon planned to relay to customers regarding privacy rights.

Amazon's responses to my inquiries do not provide enough detail about how the company intends to use customer information, beyond acknowledging that the company uses this valuable information, Markey said. ...Amazon is collecting a massive amount of information about Kindle Fire users, and it has a responsibility to be transparent with its customers.

Paul Misener, Amazon's vice president for global public policy, in early November sent a letter back to the congressman addressing privacy concerns. Misener wrote that Silk aggregates browsing information and the logs are not associated with customer identities. Therefore, Silk will not link browsing activity to a customer's browsing habits.

In addition to cloud-enhanced performance, respect for customer privacy is embedded in the design of the Amazon Silk browser, Misener wrote. Customers care how information about them is used, and we work hard to earn trust in that regard.

It is unclear whether a congressional hearing will be called on the matter.

The Fire -- along with other Kindle products -- has been a hot commodity this holiday season. Black Friday's Kindle sales quadrupled this year compared to 2010, the company announced last week. The Fire sells for $199, significantly cheaper than Apple's tablet, the iPad.