Trip google zoo
What does a panda, penguin and a hummingbird have in common? They are all algorithms that Google has used to judge the quality of websites to make your experience on Google better. Starting in 2011 Google rolled out Panda to weed out pages with high ad-to-content ratios. Soon after Penguin and Hummingbird were released. Now, thanks to these algorithms your experience trying to find high quality websites and content is much, much easier.
SOURCE : http://visual.ly/trip-google-zoo