In March 2013 Google penalized a link network named SAPE. It seems that Google might have penalized the same network again.
There are reports in a lot of “black hat” SEO forums that people’s websites rankings on Google have dramatically fallen. The similarity between these websites is that they use the network SAPE. As mentioned above SAPE was penalized in March 2013 but they changed their system and how they operate and quickly became a link network many people used.