How is this done?

I need some helping finding out how to display affiliate links in a particular way.
Go to a site like http://www.siliconera.com/ and click one of their articles, they have some sort of plugin or script installed to serve affiliate links for both Amazon and PlayAsia related to the article.
A picture of the thing I'm talking about: http://i.imgur.com/FspIkQO.png
Anybody got an idea how this is done? I can't seem to find a plugin which detects what product I want to link to automatically.
All…
How is this done?

See original post by R3Z0N