One of Google's most recent patents affects SEO, and intends to foil black and grey hat SEO practitioners. The US patent (12/652,563) outlines a rank transition program that could be used to trick spammers at the time of website or page ranking transition.
The patent is a glimpse into a function that occurs during a ranking transition period that may cause:
This transition period is when a website changes from it's old rank to a new ranking, and Google intends to use this period to throw off spammers.
During this period, Google is hoping to see correctional techniques in order to restore a positive position within it's ranking structure. Such techniques include removing the offending or commercial links, updating the recent on-page optimization that lead to the penalties, etc. Ultimately this new patent outlines a technology that makes testing for SEO more difficult, and it places more importance on long-term SEO strategy coupled with quality content focused on human users and not robots.