Amazon's Silk browser, used on the newly announced the Kindle Fire tablet, has raised privacy concerns because it directs all traffic through its EC2 cloud service.

The feature points traffic through Amazon's web servers to speed up connections and page rendering.

But some have questioned whether this capability is too invasive. Amazon said in an FAQ that it would not collect personal user information but will temporarily store Kindle IP and MAC addresses, and an aggregate of websites that users visited for up to 30 days.

"Amazon's Silk optimizes and accelerates the delivery of web content by using Amazon's cloud computing services," the company said. "To do this, the content of web pages you visit using Amazon's Silk may be cached to improve performance, and certain web address information will be collected to help troubleshoot and diagnose Amazon Silk technical issues."

The company said security provided by websites customers are visiting, such as SSL, "would still exist." And users can opt out and have their tablets connect directly to websites, rather than going through the Amazon cloud.

Xamax Consultancy director Roger Clarke said the ability to offset processing requirements to the cloud was a clever use of technology.

"However we are concerned that privacy must be accommodated," Clarke said, adding that the function should be made opt-in.

This article originally appeared at SCMagazine.com.au