Friends about to have their Amazon reviews rejected, via Shutterstock.

A few weeks ago, author Imy Santiago bought a book, wrote an Amazon review, and found it wouldn’t post to Amazon. Weird, right? An automated note from Amazon, which you can read in full here, informed her: “We cannot post your Customer Review for (book title deleted) by (author name deleted) to the Amazon website because your account activity indicates that you know the author.”

Indeed, David Barnett confirmed in The Guardian yesterday, Amazon is using social media data to keep readers from reviewing their friends’ books. This is going to cut down on the number of Amazon reviews substantially, you might imagine. With rare exceptions, authors count on their friends to buy and support their books–and Amazon reviews are a quick and easy way to show support.

But Amazon’s algorithm adjustment also means readers who follow their favorite authors on social media will be penalized. If you like the author’s Facebook page, for instance, you may not be able to post an Amazon review. Barnett writes:

The online retailer appears to have tightened up its review policy to weed out people boosting their mates’ books with glowing notices, but whatever algorithms they’re using to work this out seem also to be catching anyone who engages with their favourite writers on social media.

…On both its .com and .co.uk sites, Amazon has the same customer review guidelines, which include the warning: “Family members or close friends of the person, group, or company selling on Amazon may not write customer reviews for those particular items.”

But how does Amazon work out their definition of “friends”? It looks likely to remain a closely-guarded secret.

In a post titled, “Amazon… A Virtual Marketplace, or Big Brother?” Santiago says she’s furious:

I pay for my eBooks. I take the time to read and review books I love. The Big Brother mentality Amazon is employing is appalling, and crosses an ethical line of unfathomable proportions.

Now there’s a Change.org petition, written by author Jas Ward, asking Amazon to reevaluate its policies. “This policy makes zero sense,” it says. “We are asking that you… review your internal policy on tracking a reviewer’s history. It is not fair nor is it just.” At the time of writing, the petition has more than 11,000 signatures, and Ward plans to forward it to Amazon when they reach 15,000.