Because I prefer local bookstores, I've ordered only a couple books from Amazon in my life. From those two purchases, however, Amazon has divined a constellation reading interests based on what "similar" customers have bought. How good are they at predicting what I might want to read? Let's check in on the latest spam:
Dear Amazon.com Customer,
We've noticed that customers who have purchased The Sandman: Endless Nights by Neil Gaiman also purchased books by B. G. Pachpatte. For this reason, you might like to know that B. G. Pachpatte's Integral and Finite Difference Inequalities and Applications, Volume 205 (North-Holland Mathematics Studies) will be released soon. You can pre-order your copy by following the link below.
So I purhcased a graphic novel (and not even a very good one) by a fairly popular fantasy author, and in turn, they think that I'm in need of a "monograph ... written with a view to provide basic tools for researchers working in Mathematical Analysis and Applications, concentrating on differential, integral and finite difference equations."
Maybe they are right!