Updated the introductory paragraph
Link spam definition was updated
Machine-generated traffic (also called automated traffic) section was updated
Misleading functionality section updated and expanded
Scraping section simplified
Plus other changes
Google wrote that they have “clarified some wording in our spam policies for Google web search to focus more on what web spam is and the tactics involved.” They “also integrated an explanation of close involvement from our blog post for easier reference, and clarified that trying to circumvent our policies can also result in ranking lower or not at all.”
Why we care. Some believe that when Google makes updates to its search policies, penalties or new algorithmic actions or manual actions make soon follow. This may or may not be the case.
In any event, it is important to stay up on the latest documentation changes Google makes, especially around its search policies. So review the revised documentation when you have some time.