Google's Grip Tightens

Indeed, Google has thus far been at a disadvantage when compared to rivals like Microsoft and Yahoo! because it has not been able to offer display and search ads together.

Advertisers also want to know whether their spending on display ads is driving search queries as they intend. Bringing DoubleClick in house will help Google solve that problem.

"If you are spending a lot on display advertising, you want to see that people are getting curious, and that they are going out there and searching for the things you want," says Kevin Lee, the executive chairman of search marketing firm Didit Search Marketing. "It's a way of letting you know that your creative display advertising is working, and having it on one dashboard through the same vendor is a better solution."

And the synergy works both ways. As a part of Google, DoubleClick could take its dominance of the display ad-serving market to the next level, Lee points out.

DoubleClick is creating an online ad exchange -- an electronic marketplace that connects buyers and sellers of online advertising -- similar to the one being rolled out by Right Media, which was acquired by Yahoo! in April.

Online ad exchanges have tended to focus on so-called remnant inventory, the leftover scraps that fetch lower rates when compared to the premium spots generally sold by an online publisher's salesforce.