The recent "farmer" algorithm (name thanks to S.E.L.) takes aim at content farms, which in some cases have received some top rankings for spammy and low quality content. Google promised to do some house cleaning in 2011 by removing low quality links and devaluing websites that derive their ranking scores via lower quality links.
Even though this recent update seems to focus sharply on “scraper” sites and “content farms," other low quality and not original content websites and ranking derived from such websites may be affected.
Typically Google doesn't launch algorithms that make such broad, sweeping and impactful changes. There is a lot of pressure and interest in fighting spam today. Another obvious but helpful tool is the Chrome browser extension, which allows users to manually report spammy sites and pages.