Advertisers Corrupt Search, Microsoft Research Finds

A study with help from UC Davis suggests advertisers should closely scrutinize syndicators and traffic affiliates that are profiting from spam traffic.
The very ad dollars that support so many free sites on the Internet pay to make your search experience worse.

In a research paper to be presented at the 16th International World Wide Web Conference in Banff, Alberta, in May, researchers from Microsoft and the University of California, Davis conclude that "it is advertisers' money that is funding the search spam industry, which is increasingly cluttering the Web with low-quality content and reducing Web users' productivity."

Search spamming is the practice of using hidden text, doorway pages, or other means of deception like comment spam to make low-quality Web content rank high in a search results list.

The paper's authors, Yi-Min Wang and Ming Ma of Microsoft Research and Yuan Niu and Hao Chen of UC Davis, hope "to educate users not to click spam links and spam ads, and to encourage advertisers to scrutinize those syndicators and traffic affiliates who are profiting from spam traffic at the expense of the long-term health of the Web."

The paper, "Spam Double-Funnel: Connecting Web Spammers With Advertisers," details the tactics and methods of search spammers. And authors' findings reveal just how prevalent search spamming has become.

The 10 search keywords most frequently targeted by spammers, according to the study, are drugs, adult, gambling, ring tones, money, accessories, travel, cars, music, and furniture.

The two most spam-rich categories of content are Web pages that have to do with drugs (30.8% spam) and ring tones (27.5% spam). The average amount of unwanted content across the categories defined by the 10 most spammed keywords is 11.6%.

The report notes that few syndicators serve as middlemen, connecting the majority of Web spammers to advertisers. The top three --,, and -- were involved in 59% to 68% of the click-through redirection chains for the spam-ads sampled.

Based on the data analyzed, the report's authors conclude, "[T]hese syndicators appear to be involved in the search spam industry both broadly and deeply."

The study also found that 68% of the unique URLs in the .info domain were spam. The prevalence of spam pages in other domains is follows: 4.1% in .com; 11% in .org; 12% in .net; and 53% in .biz.

Free blog-hosting sites also contribute to the problem. For example, about one in every four spam pages listed in the search results list was hosted by, according to the study.

The paper offers some hope, however. It seems two large blocks of IP addresses -- to and to -- account for a substantial portion of spam ad click-through traffic. This "bottleneck," the paper notes, "may be the best layer for attacking the search spam problem."

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