Marissa Mayer talking about Google's new ad strategy:

"Matching graphical-display ads with image searches ``represents a large opportunity, and there's lot of potential for advertising revenue there,' Marissa Mayer, a Google vice president, told Bloomberg Radio today. At the same time, the company must ensure such ads don't drive users away, she said..."
(Source: Alley Insider)

It doesn't drive users away, it just leads more people towards Ad-block systems (e.g. Adblock Plus).

It's a bad deal for Google and a bad deal for every other ad sponsored portal. One of Google's biggest achievement was a conservative ad placement strategy. In my opinion it was one of the keystones of Google's success.