Google's moves began on Friday when it announced a deal to buy DoubleClick for $3.1 billion in cash from San Francisco-based private equity firm Hellman & Friedman. The acquisition will combine DoubleClick's expertise in ad management technology for media buyers and sellers with Google's advertising platform and publisher monetization services.

"It has been our vision to make Internet advertising better -- less intrusive, more effective, and more useful," Sergey Brin, Google's cofounder and president of technology, said in a statement. Brin and his partner, CEO Eric Schmidt, said they thought DoubleClick's technology would get Google closer to its vision -- and keep Microsoft from encroaching on its territory.

Searching the Dial

Unsatisfied with its multibillion-dollar digital marketing buy, Google continued its advertising push with a radio advertising deal that lets Google peddle ads offline.

Google struck a multiyear deal with Clear Channel Radio on Monday that lets Google sell a guaranteed portion of 30-second advertising inventory on more than 675 AM and FM radio stations. Google Audio Ads advertising can target specific geographies and specific time slots. Google said it will focus primarily on advertisers who currently run ads online but do not run ads on radio.

But Google didn't stop there. The company also announced on Monday that Google AdSense for Audio now is supported by the leading radio station systems. Beyond the Clear Channel deal, support from BE, ENCO, and VIERO systems make a way for Google to establish stronger ties with additional radio stations.

A Google Monopoly?

Google's one-two-three punch might be too much for the competition's tastes. Some industry watchers expect Microsoft and AT&T , which were also vying for DoubleClick, to ask the Department of Justice to scrutinize the Google-DoubleClick deal in an antitrust probe.

"The perception is growing that Google has too much power in the marketplace," said Greg Sterling, principal analyst for Sterling Market Intelligence. "The call for antitrust scrutiny of the Google-DoubleClick deal may be as much a PR ploy as it is a genuine request, but some feel Google's dominance constitutes a near monopoly of sorts and there's discussion of about a conflict of interest behind the scenes with the DoubleClick acquisition."

Sterling said that, beyond the politics of high-stakes deal-making, Google's moves are good for advertisers. The acquisition helps fill a Google soft spot in display ads. For its part, Google might need to offer more transparency to make its advertisers and competitors more comfortable.

"There is a specter of Big Brother that looms when any company gains too much power in any marketplace," Sterling said. "Google has to bring more transparency to what it is doing and show people that it is not trying to manipulate and take advantage or do sinister things with the data ."