What is an algorithm change?
First of all, let's start by discussing the Google algorithm. It's immensely complicated and continues to get more complicated as Google tries its best to provide searchers with the information that they need.
Three of the biggest changes that have happened in the last few years are the Panda algorithm, the Penguin algorithm and Hummingbird.
1. Panda algorithm
Panda first launched on February 23, 2011. It was a big deal. The purpose of Panda was to try to show high-quality sites higher in search results and demote sites that may be of lower quality.
The Penguin algorithm initially rolled out on April 24, 2012. The goal of Penguin is to reduce the trust that Google has in sites that have cheated by creating unnatural backlinks in order to gain an advantage in the Google results.
Google made their announcement about Hummingbird on September 26, 2013. Hummingbird is able to discern that by "place" the user likely would be interested in results that show "restaurants".
