Google's acquisition of Doubleclick was approved by the FTC today mainly because the acquisition won't lesson competition.  The issue of privacy wasn't really addressed, it was sidestepped:

"..Although interested parties have raised concerns about the proposed acquisition’s impact on consumer privacy, the Commission observed that such issues are “not unique to Google and DoubleClick,” and “extend to the entire online advertising marketplace.” The Commissioners further wrote that “as the sole purpose of federal antitrust review of mergers and acquisitions is to identify and remedy transactions that harm competition,” the FTC lacks the legal authority to block the transaction on grounds, or require conditions to this transaction, that do not relate to antitrust. Adding, however, that it takes consumer privacy issues very seriously, the Commission cross-referenced its release of a set of proposed behavioral marketing principles that were also announced today."