The European Commission is examining three antitrust complaints made against Google, it announced on Wednesday.
The Commission has not opened a formal investigation "for the time being", it said in a brief statement, but informed Google of the complaints earlier this month and has asked the company to comment on the allegations.
The complaints have come from three companies: Microsoft's Ciao price-comparison service, the UK price-comparison site Foundem, and a French legal search engine called ejustice.fr, Google senior competition counsel Julia Holtz said in a blog post on Wednesday.
"While we will be providing feedback and additional information on these complaints, we are confident that our business operates in the interests of users and partners, as well as in line with European competition law," Holtz wrote.
According to Holtz, Foundem and ejustice.fr have claimed Google demotes their sites in its search results because they are vertical search engines and, as such, competitors to the web search giant.
Holtz noted that many vertical engines, such as Moneysupermarket.com, Opodo and Expedia "typically rank high in Google's results", adding: "We are also the first to admit that our search is not perfect, but it's a very hard computer science problem to crack."
Foundem has a blog called SearchNeutrality.org, on which it wrote in August 2009 that Google exercised "unprecedented power" in the web-search market and had started "quietly exercising this control in ways that can suppress competition, stifle innovation, and erode consumer choice".
In the SearchNeutrality.org blog post, Foundem accused Google of using its penalty filters — designed cut out spam and demote sites that attempt to cheat Google's algorithms — to target "perfectly legitimate vertical search and directory services...[which] present a nascent competitive threat to Google's share of online advertising revenues".
Google's Holtz said in her blog post on Wednesday that Ciao's complaint was similar to an allegation Ciao lodged with the German competition authorities in January this year, in which it said its search partnership contract with Google contravened German law.
According to Holtz, Ciao was a long-time AdSense partner of Google's before the service's 2008 takeover by Microsoft, after which Ciao started making complaints about Google's standard terms and conditions.
Holtz also noted in her blog that Foundem is a member of a Microsoft-funded organisation called the Initiative for a Competitive Online Marketplace or Icomp — other members include the English Premier League and the PR agency Burson-Marsteller, which frequently represents Microsoft.
ZDNet UK asked a Google spokesman whether the search giant was implying Microsoft was behind the complaints to the Commission, but was told only that Holtz's post was "very factual".