By Eric Auchard
FRANKFURT (Reuters) - EU accusations that Google is abusing its dominant position in web searching to favor its own sites over rivals' center on a controversy nearly as old as the Web itself: do shopping comparison sites help consumers to make better choices, or do they simply link to other sites they don't control?
Google has long held the lion's share of the market for how consumers search for websites in most countries. But it is complaints by niche e-commerce players over how their shopping sites are ranked in Google search results that form the core of the issues on which the European Union is now set to act.
These complaints focus on the constantly evolving formulas Google uses to determine which web links rank higher on its search result pages in terms of value to users. This determines which sites most consumers searching the web end up visiting.
Since 2009, a dozen European and U.S. companies have protested to the EU about their treatment by Google. They include European-focused start-ups and U.S-based local business review site Yelp, along with travel comparison sites Expedia and Kayak, a unit of Priceline.com.
Visual-Meta, a Berlin-based price comparison fashion site now majority-owned by media giant Axel Springer, filed a complaint in 2013. Visual-Meta said Google favored its own shopping sites, Google Shopping and Product Listing Ads, over those which the German firm now operates in 19 European countries.
Robert Maier, Visual-Meta's co-founder, said his firm became profitable one year after it was set up in 2009, thanks partly to how Google search ranked shopping sites with unique content such as his own (http://www.visual-meta.com/websites/).
That began to change in 2011 when Google altered how its search system worked to showcase merchants on Google shopping sites, leading to a steep decline in traffic to price comparison sites that act as middlemen between consumers and merchants.
Maier asserts his own sites and those of online shopping sites which have complained to the EU such as Ciao.de, based in Munich, and LeGuide Group in Paris, feature reviews and other content that should be recognized as valuable to consumers.
"I am not anti-Google," said Maier, a leading entrepreneur in the Berlin web start-up scene. "I am just pro-Google playing by the rules and showcasing the best products in its search results, rather than abusing its market dominance."
Google was unavailable to comment specifically on Maier's charges. However, the company said in a blog post that it strongly disagreed with the EU's statement of objections and would make the case that its products have fostered competition and benefited consumers.
Google keeps secret how its manages search rankings, partly to block spammers from tricking its system to drive irrelevant links up. Google also features links to its own sites when it considers them relevant to particular searches by web users.
Critics of this cat-and-mouse rankings game have long grumbled that these frequent changes in search rankings make it hard for rival sites to compete with free, ad-supported Google sites such as YouTube, Google Maps and Gmail. Google's net revenues topped $52 billion last year, mainly from online advertising sales.
A separate set of complaints centers on how Google's control over Android - the mobile phone software running on more than 80 percent of the world's smartphones - allows it similarly to favor its own services over those of competitors.
(editing by David Stamp)