Microsoft has filed a formal complaint with the European Union Commission accusing Google of abusing its position as the region's dominant search engine. In a blog post enumerating the company's objections, Microsoft chief counsel Brad Smith cited several examples of Google's alleged unfair business practices, including using its ownership of YouTube to disadvantage competitors' search results and preventing advertisers from porting data to competing ad platforms.

The search giant was already under investigation after the original complaint was brought against them last year by three companies -- French legal search site eJustice, British price comparison site Foundem and a German price comparison site known as Ciao. Considering the latter two have links with Microsoft the company was already somehow involved, but now they've made it official by "adding its voice" to the matter.

This marks the first time that Microsoft has filed a formal antitrust complaint with a government agency against one of its rivals. It's also an ironic turn of events for Microsoft, whose overwhelming software market dominance and business tactics in the 90s made it a frequent target of the same types of complaints its now making against Google. As BBCs Rory Cellan-Jones puts it: "it's a measure of how the balance of power on the web has shifted."