It’s official: The much-reported on (by us) Google-Doubleclick merger has been approved today by a 4-to-1 vote by the FTC, reports the E-Commerce News’ Keith Regan.

Acquiring DoubleLick, the leader in click advertising, is seen as a huge step for Internet behemoth Google, and is expected to extend its long reach even farther across the Internet.

The proposed merger was hotly opposed by Microsoft, Yahoo!, AT&T and a chorus of other competitors. Yet that didn’t stop the FTC from issuing its decision today, leaving “many unanswered questions regarding the vulnerability of consumers’ private data,” Regan quotes Sterling Market Intelligence Founding Principal Analyst Greg Sterling.

The Federal Trade Commission authorized the deal after its investigation found that Google’s US$3.1 billion purchase of DoubleClick would be “unlikely to substantially lessen competition,” as some rivals, including Microsoft (Nasdaq: MSFT) Latest News about Microsoft, had argued. The decision disappointed many privacy advocates, who had urged the FTC to consider the data-tracking implications of the merger.

… “The markets within the online advertising space continue to quickly evolve, and predicting their future course is not a simple task,” the FTC says in its ruling. “Accounting for the dynamic nature of an industry requires solid grounding in facts and the careful application of tested antitrust analysis. Because the evidence did not support the theories of potential competitive harm, there was no basis on which to seek to impose conditions on this merger.

“We want to be clear, however, that we will closely watch these markets and, should Google engage in unlawful tying or other anticompetitive conduct, the commission intends to act quickly,” the FTC adds.

The approval underscores what the search company has argued all along: that the merger will not decrease competition in the online ad space.

However, even with the FTC’s ruling, the deal isn’t 100 percent final: Google must also win approval from the European Union regulators before the two companies can begin merging. “Google has said it is hopeful it can close the merger by early 2008,” Regan writes, but

Google may not be out of the woods just yet. The European Commission has signaled it is engaged in an intensive review of the deal and, earlier this week, a group of privacy advocates said they would consider a lawsuit if FTC Chairwoman Deborah Platt Majoras did not recuse herself from the DoubleClick vote. Those groups said Majoras has a conflict because her husband works at a law firm representing the ad agency.

Not surprisingly, opponents were quick to issue statements condemning the approval:

“Despite the FTC’s claims, privacy is most certainly an antitrust issue,” Center for Digital Democracy Executive Director Jeff Chester said. “A key component of the online market dominance that companies such as Google have achieved is the aggregation and analysis of consumer profiles, including the merger of far-flung data sets and vast data warehouses that only a handful of companies now have at their disposal.”

The FTC essentially “sanctioned the creation of a new digital data colossus,” he added. “The FTC is supposed to protect the privacy of Americans in the digital age. The excuse offered by the majority of the commission — that consumer privacy can’t be addressed by current antitrust law — reveals a lack of leadership and determination to protect U.S. consumers.”