Matt Cutts of Google Discussing SEO: Session 8

Contributed by MickeyMouse August 3, 2006  
Tagged: Google

In this session Matt explains the difference between an index update, an algorithm update, and a data refresh. He also hints at what happened on June 27th and July 27th that has troubled many webmasters.

Session 8 Video

Previously google would crawl the web and refresh the index about once a month. This was called an index update. Algorithms and data would change all in one shot. Typically those updates were big enough and obvious enough to be named, for example. These types of updates are very rare now.

Now, some of the index is updated on a daily basis so index updates are no longer required.

The bigger changes people tend to see now are the algorithm updates. When google decides to make a positive change in this mystic code, this update can be rolled out anytime.

A data refresh is the smallest change. These are the characteristics that google uses to analyze pages. The re-calculation of pagerank, for example, would be a data refresh. Some data refresh episodes such as pagerank occur on a daily basis. Others may only be calculated and reassessed every few days to weeks.

Here’s my take on Matt’s Car Metaphor:

Index Update: Changing the whole car. (Huge changes)
Algorithm Update: Changing a part of the car such as an engine.
Index Update: Changing the gas. (changing what the engine needs)

Many webmasters have been complaining about changing search engine positions from changes noticed from the data refresh episodes on June 27th and July 27th. Matt suggests if your site lost positioning from these data refresh episodes that you might be over-optimized from too much SEO procedures.