A few weeks ago, I was in a sporting goods store and happened to sit in a camping chair. The sales person came over to me and suggested I check out their new camping chairs found on the other side of the tents they had displayed. There was nothing unique about this -- as having a salesperson recommend other products to you based on ones you're looking at is a fairly common occurrence in shopping. Apparently, though, the folks at the patent office never do that kind of shopping, because they've awarded Amazon a patent for presenting recommendations based on your browsing history. Yes, the difference is that it's "online," but just because you take something from the offline world and move it to the online one, doesn't make it patentable. In fact, it would seem that any such easy comparison should be used as part of an obviousness test.