It's unfortunately a popular restriction. I was recently writing an Amazon review and wanted to mention that a certain product is nice because they have open source firmware builds that are easily modifiable, and I linked to the manufacturer's site to show people where to find them. Amazon was not pleased. Stupid really because this manufacturer doesn't have their own store and all the purchase links on their site go to Amazon. I am allowed however to include Amazon links to completely different products; Amazon is not about to protect their sellers but they certainly will protect themselves.
Biting the hand that feeds IT
