Microsoft has filed an antitrust complaint against Google with the European Commission, accusing Google of taking technical measures to squeeze Microsoft and other competitors out of the advertising and search markets.
Google has been engaging in a "broadening pattern of conduct aimed at stopping anyone else from creating a competitive alternative," Microsoft General Counsel Brad Smith alleged in a blog post detailing Microsoft's concerns.
Microsoft joins four other companies that have filed complaints about Google with the European Commission.
UK price comparison site Foundem, French legal search engine ejustice.fr, and German product review and shopping site Ciao, now owned by Microsoft, filed their complaints in February 2010, prompting the Commission to launch a wider investigation of Google's practices in November.
Then in February this year ejustice.fr's parent company 1plusV filed another complaint against Google.
The Commission will ask Google for its views on the complaint, but no further information will be released, said a spokeswoman for Competition Commissioner Joaquín Almunia.
Google said, "We're not surprised that Microsoft has done this, since one of their subsidiaries was one of the original complainants. For our part, we continue to discuss the case with the European Commission and we're happy to explain to anyone how our business works."
Microsoft's antitrust filing, its first ever according to Smith, shows how frustrated the company is with Google. Smith wrote that some people will point out the irony in the filing given Microsoft's extensive legal battles in Europe concerning Web browsers and interoperability of its systems with competitor's products.
"Having spent more than a decade wearing the shoe on the other foot with the European Commission, the filing of a formal antitrust complaint is not something we take lightly," Smith wrote.
Microsoft and Yahoo together hold about a 25 percent share of the market for search in the US. Microsoft's Bing search engine powers searches on Yahoo after the two companies reached a deal in July 2009. But Europe is different: Microsoft, Yahoo and other smaller players hold less than a 5 percent share, while Google has around 95 percent.
Google, Smith alleged, has walled off some of its content to prevent indexing by Microsoft's Bing search engine, and consistently undertaken measures to lock advertisers into using its systems.
Bing is prevented from "properly accessing" Google's YouTube video website, Smith alleged. Microsoft's latest mobile phone operating system, Windows Phone, also has problems accessing the site, with Google restricting the rich metadata associated with videos to prevent Windows Phone devices from offering the same user experience as, say, Android phones do.
"We just need permission to access YouTube in the way that other phones already do, permission Google has refused to provide," Smith wrote.
Microsoft also alleges that Google prohibits advertisers that are using its online advertising services from formatting their data in a way that could easily be used with competing ad platforms, including Microsoft's adCenter.
As for search, Smith also complained that Google prohibits leading websites from distributing other search boxes on their sites.
"It is obviously difficult for competing search engines to gain users when nearly every search box is powered by Google," Smith wrote. "Google's exclusivity terms have even blocked Microsoft from distributing its Windows Live services, such as email and online document storage, through European telecommunications companies because these services are monetized through Bing search boxes."