Amazon is testing their own "Like" button, which makes sense given that recommendations are a huge part of their business. They've decided to invest in their own solution versus integrating Facebook's.
It does make you think...Facebook is making themselves a critical part of so many websites - everything from e-commerce sites to brand experience and campaign sites. That's great for Facebook and even for brands for the time being (increased engagement, traffic, personalization, curation). But at some point, brands will wake up to find Facebook is inseparable from their business and their infrastructure.

