The European Commission today fully approved Google's proposed buyout of DoubleClick, all but ensuring the completion of the unprecedented move. The acquisition has been previously approved by the US Federal Trade Commission and received its blessing from the European agency in the belief that a combined Google/DoubleClick entity would not block out competing ad networks. As neither company has directly fought for similar business, the union of the two companies also won't create a monopoly, the Commission argues.

The merger of the two will nonetheless create the single largest online ad network available, with Google's AdSense and AdWords providing dynamic ads either on third-party pages and Google's own search site while DoubleClick supplies more traditional, graphics-based ads.

In addition to regulatory hurdles, Google has also encountered staunch opposition from Microsoft and Yahoo, both of whom have contended that a unified Google and DoubleClick would make it difficult to compete in web advertising. Microsoft in particular has reacted sharply to Google's move, buying ad firm aQuantive last year and offering more than $41 billion in a hostile bid for Yahoo in an attempt to create a major alternative to the Mountain View, California ad publisher.