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Google Algorithm Change History

Google algorithm updates and data refreshes

Google Algorithm Updates of 2015

This year's new list of updates and changes to Google's search result algorithms in 2015.

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# Date Update Update type Noticeable effect
4 Nov 2, 2015 Mobile-friendly 2 Ranking Signals Unspecified
3 Jul 18, 2015 Panda 4.2 Data Refresh ~2% - 3% English queries
2 May 3, 2015 The Quality Update Ranking Signals Unspecified
1 Apr 21, 2015 Mobile-friendly Update Ranking Signals Unspecified

Mobile-friendly Update 2: November 2, 2015

Ranking Signals

On November 2nd, Google went live with an update to its mobile-friendly algorithm. The update, which was first announced in September, penalizes websites that use large banners to prompt visitors to download a mobile app on transition from the search results. Offending sites that use app install interstitial to covers a significant portion of the page's content will no longer be considered mobile-friendly, and the mobile-friendly notification will be removed from the SERPs.

Further Reading


Panda 4.2: July 18, 2015

Data Refresh

An unusually slow Panda rollout was confirmed by Google to have commenced over the weekend of the 18th of July, and said to affect ~2% - 3% of English queries.

In the days following the Panda 4.2 refresh, Mozcast showed no significant flux; however, Google did specify that this update would roll out over a period of months. Google's Gary Illyes had announced an upcoming Panda refresh at SMX Advanced Seattle in early June, and on October 1st, over 2 1/2 months after the update began, confirmed it was still rolling out, and would continue to for some time.

Google also told us they are shifting their infrastructure towards more continuous changing and gradual rolling out of Panda, incorporated into their core ranking algorithms. Google said they are not there yet, but they’re moving in that direction, and these are the first steps in that direction.

According to John Mueller, the reason behind the ultra-slow rollout of Panda 4.2 is not to confuse or make life more difficult for webmasters and SEOs, but rather for technical reasons, to be able to analyze content quality more thoroughly.

Panda 4.2 Details

  • Date refresh only
  • Affected ~2% - 3% of English queries

Further Reading


The Quality Update: May 3, 2015

Ranking Signals

The Quality Update was confirmed by Google about 2 weeks after noticeable flux in the SERPs and spikes in Mozcast et al. Originally named as another phantom update ("Phantom 2" to be precise) because of Google's lack of acknowledgement, the Quality Update represented a change in how Google assesses content quality.

Some large sites saw traffic decreses, including WikiHow, eHow, Answers.com, and notably, Hubpages, with a traffic dip of 22%.

Panda 4.2 Details

  • Changes to core ranking algorithm in terms of how content quality is assessed
  • No particluar types of sites were targeted with this update ("how-to" sites, etc)
  • As with other quality signal updates, thin content site, or those lacking much value were targets
  • Not a spam-related update

Further Reading


Mobile-friendly update AKA Mobilegeddon: April 21, 2015

New mobile-friendly algorithm

Google's long anticipated mobile-friendly algorithm update began its first—and global—roll out on April 21, 2015.

First announced by Google in February, the mobile algorithm update affects organic results on smartphones only, adding preference for mobile-ready websites. Non mobile-ready sites aren't guaranteed to drop in rankings, but merely have one less advantageous signal for rankings.

Mobile-friendly Update Details

  • Smartphone only: Tablets and larger devices aren't affected
  • Organic results only: Local "pack" results, news, and all results aside from the standard 10 organic results per page aren't affected
  • Global rollout: This update affects English as well as non-English results worldwide
  • Page-based: Individual web pages will be evaluated for mobile-friendliness, not entire sites
  • Don't block JS or CSS Even in the event that CSS and JavaScript aren't used for your site's mobile appearance, keep those folders and resources indexable for Google's robots to crawl, or the site will fail the mobile-friendly test

Further Reading


See More Google Algorithm Updates by Year

As Google's algorithms improve, search-friendly website rankings do as well. Learn about search engine optimization.

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