Is Google Cloaking Results to Firefox Users?

by Jonah Stein on February 26, 2010

I discovered this morning that Google isseems to be cloaking results for some users based on either your browser ID user agent or possibly based on the extensions you are running in Firefox.

Like many search marketers, I frequently use Google custom queries.  By far, the most common query I use is the site: command which shows the pages from a particular domain or folder within a domain.   While preparing for SMX next week, I have been researching the effect of pagination and trying to demonstrate whether or not paginated pages are in the index. 

I am doing a case study for my clients,, examining their San Francisco Preschools ratings.  In order to see if any of the paginated pages are in the index, I search for “ inurl:p=2″

When I run this search using Firefox, I get the following results:

Site: command with Firefox

Site command with Firefox

When I repeat this query on Chrome, I see VERY different results.  So, it looks like Google is cloaking results for Firefox Users.

Update: 11:11 AM: The is some debate about whether changing content based on a browser user agent detection is really cloaking. I may be mixing my euphemisms, but I wouldn’t want to be making that distinction in a Google re-inclusion request. The impact of this is on regular users is slight virtually non-existent, but it looks like if this is not an isolated bug, professional SEO’s are going to have to start using Chrome on occasion (the good news is that Safari seems unaffected). If anyone wants to test this with a clean version of Firefox that doesn’t have any SEO extensions, let me know what you get. Maybe this is only because I have the SEOBook Toolbar and/or SEO For Firefox installed.

Update 2:01 PM: Commenters are reporting that some people confirm my results while others are seeing the same thing in FireFox and Chrome. This leads to an open debate about whether they are “personalizing” Site: results, showing different results based on IP/browse history, etc., or just screwing with me because I am a “known” SEO.

Updated 3/3/10: Confirmed that this is not a personalization issue with Byran Hordling, lead engineer on Google Personalization.

Update: 2/27/10, 1:30 PM. Michael VanDeMar pointed out that the pagination pages are being excluded by the Robots.txt. This explains the lack of metadata being shown, but does nothing to address why Chrome & Safari show different results from IE.

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