The concept of a search engine is very simple. Database the location of pages and return the most relevant results.
Primitive search engines only understood words on the pages in their database and returned pages that included those searched words. Google essentially came along with the ability to reorder those search results based on how many other pages on the Internet linked to them.
Since then Google and other search engines have improved these foundational ranking factors and developed thousands of ways to reorder search results so only the most relevant are displayed to the user. For example the "freshness" of content or the location of where the search took place.
Panda is just another way Google reorders results based on the quality of a site's content.
Throughout this article we speculate in detail what can be learned from the "Panda Patent". The verbiage used is often vague and sometimes makes it hard to retain meaning, so here's a quick concept breakdown that should help throughout.Panda refreshes gathered information about links and queries associated with a site.Upon a user search, each result listing (URL / Page) is given an initial score based on relevance to search and page quality.Calculations of #1 and #2 determine if the result listing (URL / Page) is above or below a threshold.Results are reordered by final values.Looking Back and the New "Panda Rank"
Way back in February 2011, Google released a major change in how they order search results. In it they explain:
This update is designed to reduce rankings for low-quality sites—sites which are low-value add for users, copy content from other websites or sites that are just not very useful.
They go on to say:
...it is important for high-quality sites to be rewarded, and that's exactly what this change does.
Panda looked at the quality of content as it related to a site.