As recent weeks of revelations have shown, there's a pretty wide gap between our expectations of privacy, and the privacies that an increasingly digitised world actually affords us. Whatever your feelings about your own privacy, the complexity and opacity of technology means it's often hard to know exactly what information you might be sharing at any given time. And while browsing in a local library, buying a book – with cash – on the high street, and reading at home or on the bus are pretty anonymous activities, as soon as ebooks are involved they're not.

At the end of 2012 the Electronic Frontier Foundation published the latest edition of its E-Reader Privacy Chart, and the results aren't great. Almost every service tracks searches for books, meaning not just what you read, but what you're interested in, is stored. Every book you purchase is linked to your account: trying to change your history is frustrating and in most cases impossible. Because books are tied to a user's account, removing them from one's library on most services means you won't be able to read them any more – and the purchase record will probably still exist in any case. Finally, every e-reader is, by design, capable of tracking your reading page by page: bookmarks, highlights and all. Individual policies about the retention of this information, and who it might be shared with, are worryingly unclear.

It's this lack of clarity and awareness around ebooks that should be of some concern. In the very long list of pieces of information about us that corporations and governments seem so interested in acquiring, what, how and when we read may seem trivial, but the apparent simplicity of such information, and its invisibility, stands in for much more which we do not see or fully understand.