The 20th century's favourite dictator is still making a splash in the 21st, with Adolf Hitler's Mein Kampf riding high in political science charts on the Kindle store. According to the author Chris Faraone it's because – like EL James's porn hit Fifty Shades of Grey – "clandestine" readers are perusing it within the anonymous embrace of an e-reader.

People might not have wanted to buy Mein Kampf at Borders or have it delivered to their home or displayed on their living room bookshelf, let alone get spotted reading it on a subway, but judging by hundreds of customer comments online, readers like that digital copies can be quietly perused then dropped into a folder or deleted.

But the privacy electronic readers are availing themselves of isn't exactly private. The person opposite you on the tube may not know you're following der Führer on your Kindle, but Amazon sure as hell does.

Just take a look at the Kindle terms of use. As you wrestle with the rantings of Austria's most lethal watercolourist, your device is providing Amazon with "information related to the Digital Content on your Kindle and Supported Devices and your use of it … such as last page read and content archiving". It's also reporting back on information "including annotations, bookmarks, notes, highlights, or similar markings", and may be storing those reports on "servers that are located outside the country in which you live" – say hello, China – all so they can "personalise and continually improve your shopping experience", or to "send offers to selected groups of Amazon.co.uk customers on behalf of other businesses", or to, erm, "comply with the law; enforce or apply our Conditions of Use and other agreements; or protect the rights, property or safety of Amazon.co.uk, our users or others" – oh, hello NSA.

It's not just about Jeff Bezos, of course. Whether you're exploring fascism on your iPad or your Android phone, Big Brother is watching. These kind of concerns tend to raise little more than a shrug around these parts, but you might want to think twice before downloading your electronic copy of Mao's Little Red Book of Guerilla Warfare.