P.R. Honesty
O’Reilly’s Computer Book Market Analysis

Amazon’s “What do customers ultimately buy…” Feature

Have you noticed this feature on Amazon yet? I’m talking about the “What do customers ultimately buy after viewing items like this?” area on the product page. I’m not sure how long it’s been active but I just started picking up on it yesterday.

I assume Amazon has coded all their products with a field indicating which ones are alike. They then use the wisdom of crowds (again) and help prospective customers better understand what similar products are hot. I like the idea but I wonder what impact it will have.

For example, I’m looking at the product page for a Microsoft Press book, Beyond Bullet Points. (This book is currently #1 on Amazon’s Computers & Internet bestseller list – Juliana, I’m not sure if this one is yours, but if so, congrats!) The “What do customers…” section lists the following titles:

36% buy Beyond Bullet Points

17% buy How to do Everything with Microsoft Office PowerPoint 2003

12% buy Presenting to Win: The Art of Telling Your Story

9% buy The Cognitive Style of PowerPoint

8% buy PowerPoint Advanced Presentation Techniques

Makes sense. The #1 book on the bestseller list is also the #1 book on this short list. Hopefully this helps reassure customers that it’s a popular book and a good choice. But what about those books that don’t make the list? Look around and you’ll find plenty of these. What does that mean? Well, every book obviously can’t make the Top 5 list for a given topic, right?

I have no problem with Amazon (or any other retailer) reporting the top titles on a subject, but I wonder if it’s ultimately going to create even more of a gap between the bestsellers and the rest of the list. If you’re looking at the product page for title X and you notice that it’s not one of the 5 books listed in the “What do customers…” list, are you more inclined to second-guess your decision to buy title X? After all, 70-80% or more of customers who already came this way apparently picked some other book, one of the other 5 listed. Do you really think title X is the right one for you when apparently the vast majority of earlier customers didn’t think so?

Am I overanalyzing this? Perhaps. But I think this might be an example of too much information causing us all to act like a bunch of lemmings.

P.S. – I didn’t buy into the Amazon Prime program when it launched last year but I couldn’t resist signing up for a free 90-day trial membership today. I just need to remember to opt out by 7/19 or I’ll get hit with the $79 fee… Has anyone else signed up for the trial membership? I was surprised to see the offer – I wonder if it hasn’t been as popular as Amazon had originally hoped…


Laura Lemay

Hey Joe. Amazon has said in their quarterly reports that Prime hasn't been nearly as popular as they had hoped.

Watch out for the free trial, though. I got one over the holidays and became instantly addicted to it. I still think its too expensive -- $50 would have been fine -- but I still renewed it when it came up. Damn you, Amazon!

Juliana Aldous Atkinson

Thanks Joe! The LA Times profiled author Cliff Atkinson this past week which definitly impacted sales!

Bill Bender


I wonder about the part of this Amazon’s “What do customers ultimately buy…” feature in terms of how they group items. You wrote "I assume Amazon has coded all their products with a field indicating which ones are alike". Have you heard anything further about that?

I can't imagine Amazon incurring the nightmarish maintenance of tagging all their items to make this feature work unless they allow their data feeds to incorporate this information for those items that will then have this feature enabled.

Perhaps they simply use the wisdom of the crowds for this part of the feature as well. Once they've gotten a critical mass of data for certain items, they can safely assume that any items viewed and purchased in the same session are related and, at that point, they allow this feature to be displayed.

I've also come across items where the "What other's purchased" list includes a questionably-related item. For instance, if you look at the Amazon.com page for "The Secret (Hardcover)" book, the "What Others Buy" section mentions that "1% buy Harry Potter and the Deathly Hallows (Book 7) by J. K. Rowling". Of course that could be mistagged by human error.

Thanks for an interesting blog.


Joe Wikert

Hi Bill. No, I haven't heard anything further on this. I suspect you may be right though and that it would be overwhelming to manually code each and every item. The fact that odd matches seem to be surfacing every now and then would only underscore that point, I suppose.


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