• by Joe Mandese  @mp_joemandese, Laurie Petersen , April 13, 2007

Ending weeks of a bidding battle with Microsoft, Google reached an agreement to buy online advertising network DoubleClick for $3.1 billion in cash, the companies announced today.

The deal expands Google's foothold in online advertising. The price is almost double the $1.65 billion Google paid for YouTube last year. DoubleClick, founded in 1996, provides display ads on Web sites. The deal gives Google access to DoubleClick's relationships with Web publishers and advertisers. Perhaps equally important, it keeps them away from Microsoft.

In 2005, DoubleClick was taken private by two private equity firms, Hellman & Friedman and JMI Equity, in a deal valued at $1.1 billion.

The acquisition is latest chapter in what has been a storied company that began in the mid-1990s as spin-off from Poppe Tyson, a unit of one-time Madison Avenue giant Bozell, Jacobs, Kenyon & Eckhardt before it was turned into high-flying publicly traded Internet darling DoubleClick.

The deal comes as DoubleClick has been looking to expand its presence not just in the online field but in the broader advertising marketplace via video ad serving, and even a new online buying exchange that is modeled after Wall Street's Nasdaq.

That most recent activity makes DoubleClick an especially intriguing acquisition for Google, which also have been trying to expand its online bidding model into traditional media via its acquisition of radio advertising rep Dmarc, its tests with print media sales, and its recent advertising alliance with direct TV satellite broadcaster EchoStar.