Mountain View, Calif. -- In the absence of any official opposition from regulators, Mountain View-based Google plans to press forward with its proposed search advertising deal with Sunnyvale-based Yahoo, CNET News.com reported. "My understanding is that because it's a commercial deal, we have a choice of when we implement it. We voluntarily delayed it so the government could take a look at it," Google CEO Eric Schmidt told reporters. Last week, The Wall Street Journal reported that the Justice Department had hired antitrust expert Sanford Litvack to head a possible challenge to the deal. Also, no fewer than five Congressional committees said that they would be examining the deal, which has been opposed by the 400-member Association of National Advertisers.