If you are browsing videos on YouTube and spot affiliate links to Amazon or iTunes under the movie frame, don't be surprised - it is part of Google's new monetization efforts for YouTube.
I wrote about this at Search Engine Land last night. In short, it starts with select publishers - specifically music video labels and can move on to other videos. You can read more about the specifics at The Google Blog. Here is a picture of the current affiliate links:
So far, the forum discussion around this topic is pretty low.
Forum discussion at WebmasterWorld.