Google’s $3.1bn acquisition of online advertising group DoubleClick has finally gone through, having been approved by the European Union.

The deal was first announced in April 2007, but it has now taken almost a year for the merger to pass the scrutiny of the regulatory bodies.

The US Federal Trade Commission approved the deal three months ago, while the European Commission said this week that the deal would not restrict competition or be harmful to consumers.

Microsoft and other critics of the deal had attempted to get authorities to look at the potential implications of the merger for internet users’ privacy.

Privacy groups expressed concerns that the merger would allow Google to use its own data about web users’ search activities with DoubleClick information on the website that person uses.

The move marks a significant entry into the online display ad market for the search engine. According to the Google blog:
“Advertisers and publishers who work with us have long asked that we complement our search and content-based text advertising with display advertising capabilities.”

“DoubleClick gives Google the leading platform for display advertising, enabling us to rapidly bring advances to the market in technology and infrastructure.”

The confirmation of this merger may also have implications for Yahoo and Microsoft. The threat of Google dominating the online ad market may inspire the two to reach an agreement over a merger.