German researchers from Leipzig University, Bauhaus-University Weimar, and the Center for Scalable Data Analytics and Artificial Intelligence questioned whether Google results are worse now than ever before.

The team examined 7,392 product review queries on Google, Bing and DuckDuckGo for a year, and shared the results in a new study.

The group conducted two main analyses, investigating the type of content that is retrieved by product-review queries and how much SEO influences rankings in this web genre.

They also examined how search results change over time, and whether the changes made by search-engine operators improve the overall quality of the results to support brands’ websites, publishers, blogs and other online services.

The findings suggest that all search engines have significant problems with highly optimized affiliate content — more than is representative for the entire web, according to a baseline retrieval system on ClueWeb22, the latest Lemur Project line of datasets supporting research on information retrieval.

Only a small portion of product reviews on the web use affiliate marketing, but the majority of all search results do.

Of all affiliate networks, Amazon Associates is the most popular, but all search engines fall victim to large-scale affiliate link spam campaigns.

The group also found that the line between “benign content and spam in the form of content and link farms becomes increasingly blurry” — a problem the team expects will worsen with the advent of generative artificial intelligence (GAI).

Despite Google’s continuous updates and GAI integrations to make better (some believe it will completely change) the world of search, the German researchers found “a torrent of low-quality content, especially for product search, keeps drowning any kind of useful information in search results.”

“We find that the majority of high-ranking product reviews in the result pages of commercial search engines (SERPs) use affiliate marketing, and significant amounts are outright SEO product review spam,” the researchers wrote.

The research showed a strong link between search engine rankings and affiliate marketing, as well as a trend toward simplified, repetitive and potentially AI-generated content.

The group also conducted a longitudinal analysis of the ongoing competition between SEO and the major search engines.

The study — which was conducted over a period of one year — found search engines do “intervene and that ranking updates, especially from Google, have a temporary positive effect, though search engines seem to lose the cat-and-mouse game that is SEO spam.”

“SEO is a constant battle and we see repeated patterns of review spam entering and leaving the results as search engines and SEO engineers take turns adjusting their parameters,” per the report.

Overall, the researchers found that the analysis of the product-review search results revealed three trends.

The group notes that search engines are increasingly losing the battle against SEO content, and predicts a long-term increase in spam and a decline in overall quality.

The data shows “patterns of review spam entering and leaving the results as search engines and SEO engineers take turns adjusting their parameters.”

All search engines have had some success eliminating spam. “Bing and DuckDuckGo have substantially improved their results, albeit on an overall lower level than Startpage.

The paper is accessible through a link made available by Mashable.