I have been using the Amazon Machine Tags WordPress plugin on numerous sites for a long time and have been happy with the results up until the last couple of months. I believe that Amazon has made some changes to their API over the last year or so and it has caused a lot of issues with the Amazon Machine Tags plugin. I even wrote this article in mid February discussing a work around that would allow the Amazon Machine Tags plugin to continue working until the developer was able to make some changes. Since that time I have been monitoring my posts to see if the Amazon products are always displaying and unfortunately even with the fix mentioned in the February article items were still not displaying at all times. Below I noted an alternative that provides solid functionality.