Google Buys DoubleClick for $3.1 Billion – New York Times: “The sale offers Google access to DoubleClick’s advertisement software and, more importantly, its relationships with Web publishers, advertisers and advertising agencies.

For months, Google has been trying to expand its foothold in online advertising into display ads, the area where DoubleClick is strongest. Google made its name and still generates most of its revenue from search and contextual text ads.”