Dewey update (2008): what was reported and what it means now

What was reported#

Google never confirmed the Dewey update. What is known comes from industry reporting and one forum post by a Google employee. On 31 March 2008, Search Engine Roundtable reported that WebmasterWorld members were seeing two Google data centers with very different results, adding that “this update seems to be pretty major.” An update to the post said many people were seeing the changes on Google.com.

On 2 April 2008, Matt Cutts, then head of Google’s webspam team, replied in the WebmasterWorld thread, as Search Engine Roundtable reported. He said colleagues “weren’t seeing many large differences in rankings between these datacenters,” and asked for examples through Google’s spam report form with a keyword to identify them.

Google never named it; the industry did. Cutts chose the keyword: “Let’s use ‘dewey’ as the word.” Barry Schwartz then suggested in Search Engine Land that the update be called Dewey. That article’s headline says Google confirmed an algorithm change, but Cutts’s quoted words did not.

When it rolled out#

Google stated no dates. Search Engine Roundtable reported the major shifts on 31 March 2008, after a month of smaller changes tracked on WebmasterWorld, so this page uses that date; the exact day is approximate. No completion date was ever stated.

What is known about its impact#

Google published nothing about Dewey’s impact, and Cutts’s only comment suggested Google saw little difference between data centers. Industry reports described a widely noticed shuffle of results, but no pattern was confirmed by Google. This page repeats no traffic figures for that reason.

What site owners should do#

Dewey is history. For a broad, unexplained ranking shift today, Google’s current core update guidance applies: compare performance before and after the change, and only reassess content for large, sustained drops. Its helpful content guidance says its systems prioritize content “created to benefit people.”

• Wait for a shift to settle before changing anything.
• Compare a full week after with a full week before, not the days of the shuffle.
• Improve content for readers rather than chasing short-term ranking movements.

How to check whether it affected you#

This is a historical question. Search Console keeps 16 months of data, so the only evidence would be analytics archives from March and April 2008. For anything recent, the Google Algorithm Updates timeline lists every update with its dates, so you can check what rolled out when.

Related updates#

• The PageRank paid links update was the previous change widely discussed, in late 2007.
• The Vince update was the next widely discussed ranking change, in 2009.