Google continuously works on improving their algorithms. When an algorithm improvement takes place, it is called an “Update”. The Panda Update or Penguin Update are two updates to the ranking algorithm.
Google’s Updates Are Car Parts, Data Refreshes Are Gas– Matt Cutts, Distinguished Engineer
Each Google’s Algorithm Update deals with a certain number of ranking signals. The Panda Update, for example, deals with the content quality of websites, while the Penguin Update deals with webspam.
An algorithm is only as good as the data is it based on. The data base on which the algorithm updates are founded is refreshed every once in a while. A “Data Refresh” describes the process of updating the data base at the foundation of the particular algorithm update.
Update and Data Refresh explained through the Panda Update:
The algorithm update “Panda” is a filter which is regularly applied to the entire Google Index and takes action against websites with low quality content.
For this, the Panda filter uses a specific data base. To improve the filter algorithm, or to rate specific factors/signals differently, the data base gets a refresh. A so-called “Data Refresh” of the original “Update” takes place.
- A: Algorithm update “Panda”
- D, E, G: data refreshes to the Panda filter
How noticeable are the consequences of an Update, or its Data Refreshes?
An algorithm update has a big (or rather the biggest) noticeable effect for webmasters and the ranking of their websites, because these updates introduce a new way of evaluating or rating their domain. The Panda Update affected 12% of all English search requests, for example.
A data refresh to an update usually has less perceptible consequences, as most of the time only minor factors/signals are adjusted. Thus, the Panda Update data refreshes affected 1% to 2% of all English search requests, on average.