There is a new service called Atma Links, similar to SkimLinks and VigLink, that automatically convert existing links into affiliate links.
Similar to their competitors, the Atma Links technology automatically converts regular product hyperlinks into paid affiliate links, and this service is free to affiliates.
The company also has a paid service called Proto Links that automatically generates new affiliate links from unambiguous references in text.
The Atma Links Proto Links technology (see a live demo) accomplishes this by analyzing webpages in real time for text that matches their database of millions of products.
More details at http://www.atmalinks.com/.