Sarah Lee/eyevine/Redux; Photo illustration by sarah mackinnon; GETTY IMAGES

For Catherine Henderson, curling up with a good book has always been an escape from reality. What the retired teacher doesn’t know, however, is that while she is lost in her Kindle, someone is reading over her shoulder.

Before ebook readers became popular in 2010—when e-reader sales quadrupled within months—publishers had only one way of measuring a book’s success: sales. Back then, it was almost impossible to do detailed market research that didn’t involve direct feedback, either through letters to the publishers or reader surveys. But the information didn’t tell the whole story about what readers wanted to read, and they said nothing about how they read. Did they read the whole book, or lose interest after a few pages? Did they skip certain chapters? Did they highlight and revisit favourite passages? Now the makers of the Kobo, Kindle and Nook are collecting hard data about exactly how their customers read.

When Henderson bought her Kindle a year and a half ago, she admits she may not have looked through the terms of use agreement, which does mention that the e-readers include software to track user habits. “Honestly, I’m a little bit lax with my personal information,” she says. “I guess I expect a certain amount of Big Brotherness.” Continue…