Google outlined that the top results produced by a search will soon only display two listings from a single website, a change implemented to increase site diversity.
Responding to customer feedback, Google announced Thursday on Twitter that Search results are on their way to becoming more diverse. Instead of the top results from a single search being saturated with various hits from one site, you'll see a maximum of two; you won't be seeing three listings from one website, unless the company's "systems determine it's especially relevant to do so for a particular search."
This site diversity change means that you usually won't see more than two listings from the same site in our top results. However, we may still show more than two in cases where our systems determine it's especially relevant to do so for a particular search…— Google SearchLiaison (@searchliaison) June 6, 2019
Google explained that with this change, subdomains will be treated as the root domain "for diversity purposes," unless Search algorithms considered them relevant. The company did not disclose what is considered important enough for Search to display three or more hits of a site.
According to Google Search's social media representative Danny Sullivan, the change started rolling out about three days ago.