Over the last three years, Google has made significant changes to its search algorithm. Such changes have had a dramatic impact search engine optimization (SEO) tactics. For small businesses aiming to show up in relevant local search results and subsequently gain new customers, understanding these changes has never been more important.

According to a study from the Local Search Association, search engines are the most used and most helpful channel for finding local business information. To be found (and selected) online, small businesses must first understand how Google determines ranking and then develop strategies that respond to these ranking factors.

Here’s a brief history of how Google’s search algorithm has changed over the last three years.

April 21, 2015 — The Mobile Update

Commonly referred to as ‘Mobilegeddon,’ this algorithm update was the first of many important changes to come. This update prioritized websites with mobile-friendly pages in mobile search results but did not impact searches from desktops and laptops. First proposed in February 2015, Google explained that this change would improve the user-experience and would only apply to individual pages, not entire websites.

October 26, 2015 — RankBrain

RankBrain is a machine-learning artificial intelligence system that assists Google in processing search results and providing more relevant results to users. Google has called it the third most important factor in the ranking algorithm along with links and content.

February 23, 2016 — AdWords Shake-up

With this algorithm change, Google altered the layout of SERPs by removing right-column ads and adding 4 ads at the top of search results. This change impacted clicks for both paid and organic search results.

May 12, 2016 — Mobile-Friendly 2

Google rolled out its second version of the mobile-friendly update nearly a year after the first one took place. According to Google, sites that were already mobile-friendly were unaffected by this update.

September 1, 2016 — Possum

Though unconfirmed by Google, this update appeared to impact rankings from local and Google maps results. A searcher’s physical location became an important factor, as Google began filtering search results based on address and affiliation.

March 8, 2017 — Fred

A significant core ranking update, Fred was instituted to target and penalize sites using aggressive monetization tactics which were negatively affecting user experiences. Sites with lots of advertising and underwhelming content were impacted the most by this change.

March 26, 2018 — Mobile-first Indexing

After a lot of testing, Google announced that they would begin migrating sites that followed best practices for mobile-first indexing. This change was designed to help mobile users find what they’re looking for faster and more efficiently.

July 2018 (Expected) — Speed Update

In January, Google announced that come July page speed will be a factor in mobile search ranking. This update will only impact pages that deliver the slowest experience to users. Slow pages may still rank high if they have rich, high-quality content.

For more information on how Google is evolving, download this free report, “What Your Small Business Should Know about Google Search in 2018.”