Since its inception in 2007, universal search results have have morphed to show a multitude of choices for searchers to choose from, like videos, images, maps, shopping results, and news.
In its latest research, Searchmetrics studied the universal search results for millions of keywords over the course of one year (2013) to gauge what has recently changed, and how.
Searchmetrics looked at the overall percentage that each type of universal search result garnered in the SERPs ("market share"), as well as the composition of each type of individual integration.
"Our general observation is that over the course of 2013, the proportion of keywords with at least one Universal Search integration increased in the U.S., after a temporary decrease in 2012," Searchmetrics said in its report.
In fact, the data showed keywords that displayed universal search results grew to 81 percent in 2013 from 75 percent in the previous year.
The most common integrations in the search results were videos, which rose 7 percent over 2013. Increasingly, the SERPs display at least one video result, Searchmetrics said.
In the U.S., YouTube videos outranked videos from other providers; yet, the data showed YouTube was slowly losing market share in the universal results over 2013, as illustrated in the following graph:
Images accounted for about 45 percent of all universal search elements present on a SERP, said Searchmetrics. The research found image integration was showing more frequently in the Knowledge Graph, versus between the listings in the main body of the SERP.
The number of news sources showing in universal search results slightly decreased in 2013, and Searchmetrics said Google's Hummingbird infrastructure may have something to do with that.
"This development coincides roughly with the release of the Hummingbird algorithm. At first there seemed to be more diversity in the news, but this has stabilized at a lower level after Hummingbird."
Searchmetrics said the overall diversity of news sources featured in universal search results dropped, but the market share of news integrations and the "absolute number" of news integrations into the universal search results "remained quite stable."
Product Listing Ads in universal search saw the most growth in 2013. In December of last year, PLAs accounted for about 18 percent of all universal search integration types, Searchmetrics said, but the overall number of PLAs increased by 200 percent in 2013.
For more information on the results, including detailed information on how Google Shopping fared against other Universal Search elements, get the paper here.