Tal y como recogen en el blog de SEW, Google ha ampliado con un par de frases la información What are Google’s quality guidelines?

If your site participates in an affiliate program, make sure that your site adds value. Provide unique and relevant content that gives users a reason to visit your site first.

If a site doesn’t meet our quality guidelines, it may be blocked from the index. If you determine that your site doesn’t meet these guidelines, you can modify your site so that it does and request reinclusion.