It's almost certainly less sinister than it appears, but it raises some interesting questions: how much privacy are you willing to give up for a slightly better online experience?
Chester Wisniewski, senior security adviser with Sophos, thinks there is. "Opera promises not to log or use the information they get from operating the proxy servers used by Opera Mini, whereas Amazon specifically states they will log this information," he says, pointing out that Amazon's T&Cs say that "We generally do not keep this information for longer than 30 days" - which is rather vague.
"Is it 30, or isn't it?" he asks.
Matthew Prince is CEO of content delivery network Cloudflare. "A lot of it has to do with timing," he told TechRadar.
"When Opera Mini and Google's Web Accelerator were introduced years ago, they had the benefit of being seemingly small and innocent, not large and strategic like the way Amazon is perceived now.
"We live in a new era where we have seen the consequences of giving up privacy via meeting friends on Facebook or searching on Google, and now people are questioning what they have to give up in order to have the web browsing experience they want."
BETTER SERVICE?: By monitoring users' browsing, Amazon could improve its recommendations for media and apps
Amazon isn't alone here: for example, Google's Google+ hopes to harness our social connections to improve the search engine's accuracy and the usefulness of its advertising, while Facebook is doing its very best to be the 21st century AOL, a walled garden nobody ever leaves.
"Our browsing data appears to be extremely valuable considering the effort that Facebook, Google, Microsoft and others put into tracking our every nuance online," Wisniewski says. Prince agrees. "Imagine that a marketer could look over your shoulder 24/7 while you surfed the internet," he says.
"They'll be able to see where you shopped, how much you paid for it, how long you were on the site, what other products you looked at - the entire web experience will be available to Amazon... as a retailer, Amazon is in a unique position to turn that data into valuable insights."
Amazon's lack of clarity worries people like congressman Edward Markey, who wrote(PDF link) to Amazon CEO Jeff Bezos about the browser technology. The congressman's questions seem fair enough to us:
"What information does Amazon plan to collect about users of the Kindle Fire? How does Amazon intend to use this information? Does Amazon plan to sell, rent or otherwise make available this information to outside companies?"
SWITCHING OFF: On the Kindle Fire the Silk browser's acceleration will be enabled by default, but you'll be able to switch it off
Dan Auerbach of the Electronic Frontier Foundation was worried too, and the EFF took its concerns to Amazon. Encrypted traffic isn't intercepted at all, Auerbach reports, and "for the persistent SPDY connection between the device and Amazon's servers, Amazon assures us that the only pieces of information from the device that are regularly logged are [the] URL of the resource being requested, timestamp [and] token identifying a session."
That's the good news. The bad? "Amazon stores URLs you visit, and these sometimes contain identifying information."
That means "Amazon will effectively have a database of user search histories across many different databases... moreover, the data collected by Amazon provides a ripe source of users' collective browsing habits." The EFF's advice is that Kindle Fire users who worry about privacy should turn the cloud-based browsing system off.
The problem with privacy is that it's a balancing act: without sufficient information, some services are useless. Take Apple's iPhone, for example: if it isn't broadcasting its - and your - location then Find My Phone and Find My Friends are utterly useless.
The best example of the trade-off, though, is Siri. The iPhone 4S's virtual personal assistant needs to know lots about you in order to do its job. As Ed Wrenbeck, former lead developer from Siri, explains:
"For Siri to be really effective, it has to learn a great deal about the user. If it knows where you work, where you live and what kind of places you like to go, it can really start to tailor itself as it becomes an expert on you individually. This requires a great deal of trust in the institution collecting this data. Siri didn't have this, but Apple has earned their street cred."
"It could well be that amazon built the technology solely for the engineering reasons - faster and improved performance, better battery life, etc - not the marketing reasons," Prince says.
"If that's the case, then [privacy] concerns may have in fact been a surprise to them. To that end, the privacy concerns will be resolved if consumers think the technology is worth it. They may be willing to give Amazon Silk a try if the web experience is that much better... it will be interesting to see how this pans out."
Should you fear the future?
The EFF thinks we need to pay close attention to what firms are doing with our data. "As companies continue to innovate in ways that make novel uses of -- and expose much more personal data to -- the internet cloud, it's critical that the legal protections for that data keep up with changes [in] technology," Auerbach writes.
"These things tend to be fine until they are not fine," Prince says. "People may be okay with Amazon looking over their shoulder, making recommendations and so on, but there may come a time when Amazon will cross the line and it becomes creepy. We've seen that happen before with other companies."
Are we walking into a world where your choice of smartphone, tablet, browser or social network locks you into a single shop and hands over your entire life for data mining and ad targeting? Wisniewski hopes not.
"These private areas - think AOL - never survive in the long term," he says. "People inherently want simplicity and freedom of choice, [and] while the simplicity of using one store for music, books or movies is appealing, people also want the ability to choose who they do business with.
"Once these systems become too restrictive people will either demand openness, or switch to the next shiny object that will provide it. There is a risk we are heading in [the wrong] direction, but I am optimistic that people are becoming more aware of the importance and value their privacy has."
Liked this? Then check out Amazon Kindle Fire: what you need to know
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Writer, broadcaster, musician and kitchen gadget obsessive Carrie Marshall (Twitter) has been writing about tech since 1998, contributing sage advice and odd opinions to all kinds of magazines and websites as well as writing more than a dozen books. Her memoir, Carrie Kills A Man, is on sale now. She is the singer in Glaswegian rock band HAVR.