On April 24, Google has rolled out an algorithm update called Penguin Update which specifically target websites over doing their SEO. Google attempt to put webmasters who are just really aggessive SEO´s in the rear and push webmasters that build quality content to the front.
Big bands appear to be untouched
It seems realtive clear that big brands overall untouched. Some experts with background knowledge just wondering, why Google apply double standards. With reason, cause many brands generate backlinks on a dubious way. I reckon that the mass of backlinks make them untouchable.
Low quality sites have a problem
With Penguin, Google underlines their focus on websites with quality content. Especially thin affiliate sites going forward to have a problem, cause mostly they have low benefit for users. You only find less (useful) informations and links to brands.
Conclusion
Google becomes more sensitiv in kind of low quality content and over doing (dubios) linkbuilding practices. The Penguin-Update especially sighted shorthead keywords like „money“ or „insurance“ which often focused by SEO´s in agencies. Im sure that they get worried!