NEW YORK (CNNMoney) -- Microsoft plans to file a formal complaint with the European Commission Thursday, accusing Google of abusing its position as the region's dominant search engine.  The software giant -- once subject to its own landmark antitrust investigation in the United States and Europe -- claimed in a blog post that Google is preventing rivals from creating a competitive alternative to its search technology. Microsoft operates the two-year-old Bing search engine, which, though a partnership with Yahoo (YHOO, Fortune 500), is the second-largest search website in the United States and Europe.  Microsoft (MSFT, Fortune 500) cited several examples of what it said was Google's abuse of its dominant position.  For instance, the company claims that Google is impeding fair competition by restricting rival search engines from "properly accessing" the Google-owned YouTube for their search results. Google supposedly won't release YouTube's so-called "metadata," which includes video categories, favorites and ratings.  The company also said that Google (GOOG, Fortune 500) released superior YouTube applications for its own Android platform and Apple's iPhone, but designed a limited YouTube app for Microsoft's Windows Phone platform. Microsoft said it wants to release its own high-quality YouTube app, but it requires access to YouTube's metadata to do that.  "[Google] understands as well as anyone that search engines depend upon the openness of the Web in order to function properly, and it's quick to complain when others undermine this," the company said in its blog. "Unfortunately, Google has engaged in a broadening pattern of walling off access to content and data that competitors need to provide search results to consumers and to attract advertisers."  Microsoft's claims extend beyond search. Both companies compete in the online advertising market, and Microsoft said that Google prevents advertisers from easily porting their ad campaign data to competing platforms, including Microsoft's adCenter.  Many companies buy search ads from Google first, since it has the largest share. But if that data isn't interoperable with competitors' platforms, Microsoft claims many advertisers simply won't bother advertising with anyone other than Google.  Microsoft also cited Google's dominant position in websites' search boxes. It complained that Google enters into exclusivity agreements with Web properties that prevent Microsoft from distributing its online products like Hotmail, cloud storage and Windows Live to those sites.  Google's attempt to gain access to a large volume of "orphaned" books, which a U.S. federal judge smacked down last week, also came up in the complaint. And Microsoft joined in a chorus of companies that want more transparency in how Google ranks its advertisements.  The complaint will be added to an ongoing investigation into Google's business practices by the European Commission. Microsoft's voice is by far the largest among those opposed to Google's position -- though a Google spokesman noted that Microsoft's complaint comes as no surprise, since Ciao, a Bing subsidiary, 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," a Google spokesman said.  Google controls 65% of the search market in the United States but 90% of the market in Europe, which is why Microsoft said it filed the complaint there.  Of course, there's a "man bites dog" aspect to Thursday's filing, which Microsoft acknowledged.  "There of course will be some who will point out the irony in today's filing," the company said. "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. More so than most, we recognize the importance of ensuring that competition laws remain balanced and that technology innovation moves forward."
Microsoft will file a complaint with the EU, claiming Google is unfairly preventing Bing from competing in the search market.